CEA – Review Sheet 3

Lesson 3.1 Introduction to Commercial Building Systems - OverviewPrefaceCommercial buildings are designed, built, and operated for any use other than residential, manufacturing, or agriculture. They serve a wide range of uses and include facilities built for schools, hospitals, churches, hotels, offices, malls, gas stations, and restaurants, to name a few. Often municipalities control development of commercial facilities through the use of land use and zoning regulations.

Each commercial building must meet the requirements established in building codes and state and local regulations. These requirements must be identified and researched prior to designing the structure to ensure compliance.

Commercial building systems often differ significantly from residential building systems. Depending on the usage, low-rise (three stories or less) commercial building design and construction can sometimes be similar to residential design and construction. However, because the typical commercial facility suffers much more intense usage, is exposed to greater loads, and must meet more stringent building code requirements, commercial building materials and construction methods are often chosen based on the need for higher strength and more durability than typical residential construction.

Understandings

1. Commercial building systems differ from residential building systems in many significant ways.2. Codes and building regulations define and constrain all aspects of building design and construction including the

structure, site design, utilities, and building usage.3. Zoning regulations are used to control land use and development.4. Wall, roof, floor, and framing systems for commercial facilities are chosen based on many factors.

Knowledge and SkillsIt is expected that students will:

Identify common commercial wall systems and building materials and differentiate between load-bearing and non-load bearing walls.Identify common commercial building framing systems.

Identify applicable building codes and regulations that apply to a given development. Classify a building according to its use, occupancy, and construction type using the International Building Code. Research Land Use regulations to identify zoning designations and allowable uses of property. Comply with specifications, regulations, and codes during a design process. Compare a variety of commercial wall systems and select an appropriate system for a given commercial application

based on materials, strength, aesthetics, durability, and cost. Compare a variety of commercial low-slope roof systems and select an appropriate system for a given commercial

application based on materials, strength, durability, and cost. Identify the pros and cons of the use of a green roof in a commercial building design.Incorporate sustainable building

practices, especially a green roof, into the design of a commercial building. Use 3D architectural design software to incorporate revisions for the redesign of a building. Use 3D architectural design software to create appropriate documentation to communicate a commercial building

design. Calculate the structural efficiency of a structure.

Use load-span tables to design structural elements.

Essential Questions

1. How do Land Use and Development regulations help or hinder development in a community?2. Why are building codes important in the construction of buildings?3. How does commercial building design and construction differ from residential building design and construction?4. What factors influence the choice of commercial construction materials?5. How do sustainable design alternatives, such as a green roof, impact the environment and quality of life?

6. Lesson 3.1 Commercial Building Systems - Key Terms

Term Definition

Ballast A heavy material installed over a roof membrane to prevent wind uplift and shield the membrane from sunlight.

Beam A structural member, usually horizontal, that carries a load that is applied transverse to its length.

Brownfield Real property of which the expansion, redevelopment, or reuse may be complicated by the presence or potential presence of a hazardous substance, pollutant, or contaminant.

Building Code Legal requirements designed to protect the public by providing guidelines for structural, electrical, plumbing, and mechanical areas of a structure.

Built-up Roof (BUR) A roof membrane laminated from layers of asphalt-saturated felt or other fabric, bonded together with bitumen or pitch.

Cast-in-Place Concrete Concrete that is poured in its final location.

Column An upright structural member acting primarily in compression.

Concrete Masonry Unit (CMU)

A block of hardened concrete, with or without hollow cores, designed to be laid in the same manner as brick and stone.

Construction Type Five broad categories of construction found in the International Building Code that are based on the fire-resistive capabilities of the materials used.

Curtain Wall An exterior building wall that is supported entirely by the frame of the building, rather than being self-supporting or load bearing.

Decking A material used to span across beams or joists to create a floor or roof surface.

Egress Exits or a way out.

Elevated Floor A floor that is above the level of the ground.

EPDM (Ethylene Propylene Diene Monomer)

A synthetic rubber material used in roofing membranes.

Exit That portion of the means-of-egress system between the exit access and the exit discharge or the public way.

Exit Access That portion of the means-of-egress system that leads from any occupied portion in a building or structure to an exit.

Exit Discharge That portion of the means-of-egress system between the termination of the exit and a public way.

Fenestration All areas (including the frames) in the building envelope that let in light, including windows, plastic panels, clerestories, skylights, glass doors that are more than one-half glass, and glass block walls. A skylight is a fenestration surface having a slope of less than 60 degrees from the horizontal plane. Other fenestration, even if mounted on the roof of a building, is considered vertical fenestration.

Hybrid Something that is the product of mixing two or more different things.

Ingress Entrances or a means to enter.

Light Gauge Steel Thin sheet metal folded into a stiff shape and used as a structural member.

Load Forces or other actions that result from the weight of building materials, occupants and their possessions, and environmental effects.

Load Bearing Wall A structural wall that carries loads other than its own weight.

Low-Slope Roof A roof that is pitched at an angle so near to horizontal that it must be made waterproof with a continuous membrane rather than shingles; commonly and inaccurately referred to as a flat roof.

Masonry Brickwork, concrete block work, and stonework.

Municipality A city, town, etc. having its own incorporated government for local affairs.

Non-Load Bearing Wall A wall that does not carry vertical load other than its own weight.

Occupancy Group A specification that indicates by whom or how the structure will be used.

Occupant Load The number of persons for which the means of egress of a building or portion thereof is designed. (IBC)

Open Web Steel Joist Open web, parallel chord, load-carrying members suitable for the direct support of floors and roof decks in buildings.

Pitched Roof A sloping roof.

Ponding The collecting of water, as on a roof, into large puddles or a pond.

Precast Concrete Concrete cast and cured in a position other than its final position in the

structure.

Reinforced Concrete Concrete into which steel reinforcing bars have been embedded to impart tensile strength to the construction.

Shore A prop for preventing sinking or sagging (noun). To support by a shore (transitive verb).

Single-Ply Membrane A sheet of plastic, synthetic rubber, or modified bitumen used as a roofing sheet for a low-slope roof.

Slab-on-Grade A concrete surface lying upon, and supported directly by, the ground beneath.

Span The distance between supports for a beam, girder, truss, or other horizontal structural member; to carry a load between supports.

Spray Polyurethane Foam (SPF)

Polyurethane foam sprayed in place on a low-slope roof then covered with a protective coating.

Stability A condition of a frame or structure in which a slight disturbance in the loads or geometry of the structure does not produce large displacements or failure.

Strength The capacity of a structure to resist the effects of loads.

Structural Efficiency Ratio of the maximum design load to the weight of the structure.

Tilt-up Construction A method of constructing concrete walls in which panels are cast and cured flat on a floor slab then tilted up into their final position.

Underlayment A panel laid over a subfloor or subsurface to create a smooth, stiff surface for the application of a finish.

Welded Wire Fabric (WWF)

A grid of steel wires or bars welded together at all points of intersection to form an open mat. The fabric is designated by the size of the grid (spacing of the wires) in inches followed by numbers indicating the gauge of the wire in each direction.

Lesson 3.2 StructuresPrefaceThis lesson is designed to introduce students to the concepts and principles of structural engineering. The activities related to this lesson are designed to aid students in learning the process of structural design and the calculations involved. The lesson focuses on beam analysis and design and the sizing of spread footings. It is important to remember that there is not enough time to cover all aspects of structural calculations in this one lesson.

A structure must safely and efficiently resist all applied loads and transfer the loads to the supporting soil. The applied loads are the result of natural forces and must be quantified in order to design a structural system.

Some important loads that must be considered when designing a structure are:

1. Dead loads2. Live loads3. Snow loads4. Wind loads5. Seismic loads6. Soil pressure loads

The building’s dead load is based on the weight of the building components; however, the other types of loads can vary in duration, magnitude, and point of application. The likelihood of occurrence for each load type differs from region to region. Through experimentation and statistical analysis, engineers continue to refine the load cases that are likely to affect a building throughout its life cycle. In most cases, the loads to be used in the design of a structure are dictated by building codes and standards.

Structural analysis uses physical laws and mathematics to determine how structural elements will internally resist and transfer these loads. Once the resisting mechanisms are understood, a structural engineer may choose appropriate structural members to safely and efficiently support the building and the loads to which it is subjected.

Understandings

1. The purpose of a structure is to withstand all applied loads and forces and to transfer these forces to the Earth.2. Structural engineering involves the critical analysis of forces and loads, the anticipated effect of these loads on a

structure, and the design of structural elements to safely and efficiently resist the anticipated forces and loads.3. Design loads are often dictated by building codes.4. Structural design includes the determination of how structures disperse the applied loads.5. The application of loads to a building results in resisting forces from the structure which can be predicted through the

use of mathematics and physical science principles.

Knowledge and SkillsIt is expected that students will:

Given a structural form, describe how the structural form resists and transfers applied loads. Use building codes and other resources to calculate roof loading to a structure and select appropriate roof beams to

safely carry the load. Analyze a simply supported beam subjected to a given loading condition to determine reaction forces, sketch shear

and moment diagrams, and determine the maximum moment resulting in the beam.

Use beam formula to calculate end reactions and the maximum moments of a simply supported beam subjected to a given loading condition.

Use structural analysis software to create shear and moment diagrams of simply supported beams subjected to a given loading condition.

Calculate the deflection of a simply supported beam subjected to a given loading condition. Use building codes and other resources to determine the required floor loading and design a structural steel floor

framing system (beams and girders) for a given building occupancy. Identify and describe the typical usage of foundation systems commonly used in commercial construction. Determine the loads transferred from a steel framed structure to the ground through a foundation. Size a spread footing for a given loading condition. Check structural calculations created by others for correctness.

Essential Questions

1. What is structural engineering?2. What is the function of a structure?3. How do you determine the loads that must be used to design a structure?4. In what ways is wind, snow, seismic, dead, and live loads similar to or different from each other?5. How does the design of a structure impact how loads are dispersed?6. How does the use of mathematics help in understanding and quantifying the forces and loads on a structure?7. How does the structure of a building affect the form and function of that building?

Lesson 3.2 Structures - Key Termserm Definition

Allowable Strength Nominal strength divided by the safety factor.

ASD Allowable Strength Design. A method of designing structural elements such that the allowable strength is greater than or equal to the strength necessary to support the required load combinations.

Axial Force A force that acts along the longitudinal axis of a structural member. Axial tension causes elongation of the member. Axial compression causes shortening of the member.

Beam A structural member, usually horizontal, that carries a load that is applied transverse to its length.

Beam Analysis The use of physical laws and mathematics to compute internal forces, stresses, and deformations.

Caisson A long cylindrical reinforced concrete foundation element formed by drilling into firm soil and pouring concrete into the hole.

Column An upright structural member acting primarily in compression.

Continuous Beam A single beam that is supported by more than two supports such that it has at least two distinct spans.

Dead Load The weight of the building or building components.

Deep Foundation A foundation that transfers building loads into the earth well below the building structure.

Deflection The distance a beam or structure deforms under loading, typically due to bending in a beam.

Deformation A change in the shape of a structure or structural member caused by a load or force acting on the structure.

Design Load The applied load determined by the required load combinations.

Equilibrium The state of a body such that the sum of all the external forces acting on the body equals zero and the sum of all external moments acting on the body equals zero.

Fixed Support A support condition in which translation of a structural member is restricted in two perpendicular directions and rotation is restricted. A fixed support provides two perpendicular reaction forces and a reaction moment when the member is loaded.

Footing The lowest, widest part of the foundation that distributes the load over a broad area of the soil.

Force An agent that causes stress in an object.

Foundation The lower part of a building, which transfers structural loads from the building to the soil.

Free-body Diagram A diagram used to isolate a body from its environment, showing all external constraints and forces acting upon it and all geometric measurements necessary to model the body.

Girder A horizontal beam that supports other beams; a very large beam, especially one that is built up from other sections.

Grade Beam A reinforced concrete beam that transmits the load from a bearing wall into a spaced foundation such as pile caps or caissons.

Internal Force A force that is internal to structural elements and is needed to determine the material stress and strain.

Kip A unit of weight equal to 1000 pounds.

Lateral Load A force acting generally in a horizontal direction, such as wind, earthquake, and soil pressure against a structure.

Live Load The weight of movable objects such as people, furnishings, machines, vehicles, and goods in or on a building.

Load Forces or other actions that result from the weight of building materials, occupants and their possessions, and environmental effects.

Load Path A continuous system of structural elements that transfer an applied load to the supporting soil.

Mat (Raft) Foundation A single concrete footing that is essentially equal in area to the area of ground covered by the supported structure.

Moment

about a point P

The tendency of a force to rotate an object about point P. It is equal to the product of the magnitude of the force acting on the object and the perpendicular distance from the point P to the force.

Moment Arm The perpendicular distance from a reference point to the line of action of the force.

Moment Diagram A plot of the internal moment in a beam versus position along the axis of the beam.

Nominal Strength The load carrying capacity of a structural member.

Occupancy Category A category used to determine structural requirements based on occupancy of the building.

Pile A long slender piece of material driven or drilled into the ground to act as an element of a foundation.

Pin Support A support condition in which translation of a structural member is restricted in two directions but rotation is not restricted. A pin support provides two perpendicular reaction forces when the member is loaded.

Roller (Rocker) Support

A support condition in which translation of a structural member is restricted in only one direction and rotation is not restricted. A roller support provides one reaction force when the member is loaded.

Safety Factor A factor intended to compensate for uncertainties in design and analysis by reducing the theoretical strength of a member for use in design.

Seismic Load A load on a structure caused by movement of the Earth relative to the structure during an earthquake.

Serviceability The ability of a structure to maintain its appearance, durability, comfort for occupants, proper function of equipment, and ease of maintenance.

Shallow Foundation A foundation that transfers building loads into the Earth at the base of a column or bearing wall.

Shear Diagram A plot of the shear force in a beam versus the position along the axis of the beam.

Shear Force The internal force, usually in a beam, which acts in the plane of the cross-section of the beam.

Simple Beam A beam that is supported on one end by a pin support and supported on the other end by a roller support.

Span The distance between supports for a beam, girder, truss, or other horizontal

structural member; to carry a load between supports.

Spread Footing A wide shallow footing usually constructed of reinforced concrete.

Stability A condition of a frame or structure in which a slight disturbance in the loads or geometry of the structure does not produce large displacements or failure.

Statically Determinate Beam

A beam which is supported such that the number of unknown reaction forces is equal to the number of equilibrium equations.

Statically Indeterminate Beam

A beam which is supported such that the number of unknown reaction forces is greater than the number of equilibrium equations.

Strain Deformation under stress.

Stress Force per unit area.

Structural Engineer An engineer that is licensed to design the structural systems for a building.

Tributary Area The area of floor or roof representing the surface area from which an applied uniform load is assumed to transfer to a supporting structural member.

Tributary Width The width of floor or roof along the length of a beam, measured perpendicular to the beam, representing the portion of surface from which an applied uniform load is assumed to transfer to that beam.

Truss An assembly of structural members joined to form a rigid framework, usually connected to form triangles..

Weight The force exerted upon a body due to gravitational attraction to a planet.

Wind Load Pressure from the wind that can cause lateral loads as well as uplift on the roof or downward pressure.

Yield Stress The stress at which a material begins to deform plastically.

Strength is the capacity of a structure to carry the loads applied to it.Stability means the structure can maintain its shape when loads or forces are applied. Loads and disturbances to the structure should not produce large movements or failure.The economic value or cost effectiveness of the structural design depends on choices made regarding how the structure will carry loads, the structural systems used, and the materials chosen.

Both the reaction forces are acting up and are therefore positive.The applied forces are acting downward and are therefore negative.[click] The uniform load must be converted to an equivalent concentrated load that takes into account the entire force.[click]The equivalent concentrated load is assumed to act at the center of the uniform load application and represents the uniform load in the calculation.This equation has two unknowns. We cannot solve a single equation with two unknowns. We need another equation.The best point about which to sum moments is one of the support locations. You can choose any support location.We will sum moments about point A in this example.Since FyA acts through the point A, it has a zero moment arm.The 4000 lb applied concentrated load and the equivalent concentrated load (from the uniform load) both cause clockwise rotation about point A; therefore, the moment caused by these forces is considered negative. Remember that the equivalent load (which takes the place of the uniform load) is assumed to act at the middle of the uniform load location.The moment caused by FyB is positive, because FyB would cause a counterclockwise rotation about point A.Because the applied loads do not occur at a support, shear forces are induced in the beam – that is, the particles in the beam try to slide against each other because the applied forces are pushing down and the reaction forces are pushing up. The shear forces get larger as you get closer to the support.A shear diagram is a way to represent the shear force at every point along the beam. It is really just a bookkeeping method to keep track of the vertical forces

The moment diagram represents the magnitude of the moment at every point along the beam. [Point out the appropriate points on the moment diagram as you discuss it.]

• For pinned and roller connections, we know there is no moment reaction. Therefore, the moment at a pinned or roller connection is always zero. Note that the moment at each end is zero here.

• The moment diagram for a beam that has a uniform load is essentially parabolic. When a concentrated load is applied there is a slight kink in the diagram that is difficult to represent.

• The moment diagram for a beam loaded only with concentrated loads is composed of straight lines. The slope of a line is equal to the magnitude of the shear at that point.

• The maximum moment always occurs at a point of zero shear.

The plastic section modulus, represented by capital Z, is a section property of the shape, that is, it depends only on the size and shape of the cross section of the member. It is a calculated value based on the area of the cross section and the distance of the material from the neutral axis. The plastic section modulus gives an indication of the moment carrying capacity of the section when the entire cross section is stressed to yield – the larger the plastic section modulus, the larger the maximum bending moment before failure.

Building codes and design standards restrict deflection of structural members.Excessive deflection, although not normally a safety issue, can adversely affect the performance of a building. Too much movement can cause cracks in walls and ceilings, roof ponding, misalignment of building systems, and incorrect operation of equipment. In addition, excessive deflection can give people an uncomfortable “motion sickness” feeling, or can simply make them feel uncomfortable about the potential safety of the building.Based on building codes and design standards, the deflection limits are L/240 for dead + live load and L/360 for live load alone.For a simple beam with a uniform load, the maximum deflection will occur at center span and can be calculated using this equation.Be sure to convert every quantity to pounds and inches so that units will correctly cancel.

Always design for moment first because it will almost always control beam design over shear.Ma is the maximum moment due to the design loads.The factor of safety for bending is 1.67.

Foundation failures are generally traced to one of two causes.The footing is essentially an inverted concrete cantilever beam. The beam can fail if the footing is not designed to resist the stresses caused by the bending moment or shear imposed by the soil pressure. The column or pier can punch through the footing if the footing is not thick enough to resist the shear forces.Soil can fail in many ways

• If the building loads apply a soil pressure that exceeds the soil bearing capacity, the soil may give way and allow excessive settlement as shown in the illustration.

• If the soil is expansive and the moisture content changes, the soil could swell or shrink, causing excessive movement.

• If the soil is susceptible to frost heave and experiences freezing temperatures, the expansion of the freezing water could cause the foundation to lift.

Lesson 3.3 Utilities and Services - OverviewPreface

In today’s society people have come to expect modern buildings to be equipped with services necessary to effectively function in the 21st century. What once were considered to be modern conveniences are now considered basic services necessary for a building to function effectively. These services, such as reliable sources of energy and water, a method to transport wastes away from the building, and pathways for communication, are often referred to as utilities and are critical to a successful project design. In addition, occupants expect water, drainage, heating, and air conditioning on demand throughout the building. The availability, level of service, and location of utilities and services must be considered throughout the building design process.

In the case of electrical supply, there are several questions that must be addressed. Is it available to the site? Is it above or below ground? If it is not available, how soon will it be available and at what cost? What phases and voltages are available?

Natural gas is used quite frequently as an energy source for heating and cooking. If the lines are available in the area, how much will it cost to extend them to provide service to the project? Where will they be run? Will the supply be adequate for future expansion should it become necessary?

Fresh water must be provided by either private or public mains running near or through the site. If it is public water, is the main adequately sized to provide the necessary water? If private, will a well have to be drilled or dug? Will a water treatment system be needed? Supply lines must be buried below the frost line and routed as directly to the structure as possible. The supply is pressurized so that the pitch of the pipes will not be a major consideration.

Sewage disposal will be provided through either a public main or an onsite treatment facility. Sewer lines, if sloped correctly, will allow the sewage to flow to the sewer main without the need of an expensive pumping station. If public or private mains are used, are they adequately sized to handle the additional waste? Will separate mains be needed to handle manufacturing waste or chemicals and will it be pre-treated on site? What will be the regulations of an onsite treatment plant if one is required? What special engineering and permits will be acquired? What types of inspections will be required?

Internal systems like water supply, drainage, power, heating, ventilating, and air conditioning require fixtures and equipment that must also be incorporated into the design and construction of the building in order to provide the expected level of service. In addition, current conservation efforts demand that these systems minimize the use of natural resources and the impact on the environment. Architects and engineers must understand the design and construction of these systems in order to facilitate the construction of an efficient and environmentally friendly building.

Understandings

1. When utilities are not available within a reasonable distance to be economically brought on site, substitutions must be designed and constructed.

2. Utilities and systems must be properly sized to minimize cost and appropriately serve the project.3. Responsible designers anticipate the needs and requirements of the users.4. The design of mechanical systems impact the architectural and structural design of a building.5. Energy codes are designed to conserve natural resources, reduce operating costs, protect the environment and

create healthier living and working spaces. They dictate the minimum requirements for the building envelope, lighting, mechanical systems, and service water heating for commercial facilities.

6. The design of internal systems is documented with construction drawings specific to each system.

Knowledge and SkillsIt is expected that students will:

Identify typical utility services for a commercial building, typical transmission/distribution methods for each utility, and methods for measuring usage.

Interpret and apply code requirements and constraints as they pertain to the installation of services and utilities. Read and understand HVAC construction drawings for a commercial project. Apply criteria and constraints to size and locate the new utility service connections for a commercial facility. Modify system designs to incorporate energy conservation techniques.

Essential Questions

1. When planning a project how does the availability of public utilities impact the design?2. What options are available for the management of wastewater from a building?3. What are the important considerations when designing an HVAC system?4. Why is it important for an architect to understand how electrical, plumbing, and HVAC systems are designed and

constructed?

5. Lesson 3.3 Services and Utilities - Key Terms

Term Definition

Air Handling Unit (AHU)

A device used to condition and circulate air as part of a heating, ventilating, and air-conditioning (HVAC) system.

Circuit The various conductors, connections, and devices found along the path of electric flow from the source through the components and back to the source.

Circuit Breaker An electric safety switch that automatically opens a circuit when excessive amperage occurs.

Cleanout A fitting with a removable plug that is placed in plumbing drainage pipe lines to allow access for cleaning out the pipe.

Distribution Panel

A box in which the wires from the meter are connected to individual circuit breakers, which are connected to separate circuits for distribution to various locations throughout the building.

Drain Any pipe that carries wastewater or water-borne wastes in a building drainage system.

Drainage Fixture Unit

A measure of the probable discharge into the drainage system by various types of plumbing fixtures.

Drainage System

Piping within a building that conveys sewage, rainwater, or other liquid wastes to a point of disposal.

Ducts Pipes, typically made of sheet metal, used to conduct hot or cold air in the HVAC system.

Electric Meter An instrument used to measure electric power.

Fenestration All areas (including the frames) in the building envelope that let in light.

Ground An electrical connection to the earth.

Heat Pump A unit designed to produce forced air or hot water for heating and cooling.

Hot Water Water at a temperature greater than or equal to 110 º F (43º C).

Individual Sewage Disposal System

A system for disposal of domestic sewage by means of a septic tank cesspool mechanical treatment to serve a single establishment or building.

Lavatory A fixture that is designed for washing hands and face, usually found in a bathroom.

Main The principal pip artery to which branches are connected.

Nonpotable Water

Water not safe for drinking, personal, or culinary utilization.

Outlet An electrical connection used to plug in devices. A duplex outlet, with two outlets, is the typical wall plug.

Plumbing Fixture

A device that is connected to the water distribution system and demands a supply of water; discharges wastewater, liquid-borne waste material, or sewage to the drainage system; or requires both a water supply connection and a discharge to the drainage system.

Potable Water Water free from impurities present in amounts sufficient to cause disease or harmful physiological effects and conforming to the regulations of the public health authority having jurisdiction.

Riser A water supply pipe that extends vertically one story or more to carry water to fixtures.

Sanitary Sewer A sewer that conveys sewage but excludes storm, surface, and ground water.

Sewage Any liquid waste containing animal or vegetable matter in suspension or solution, including liquids containing chemicals in solution.

Sewer A pipe, normally underground, that carries wastewater and refuse.

Soil Pipe A pipe that conveys sewage containing fecal matter to the building drain or building sewer.

Stack Any vertical line of soil, waste, vent, or inside conductor piping that extends through at least one story.

Storm Sewer A sewer that conveys storm water or other drainage but not sanitary sewage.

Switch Leg The electrical conductor from a switch to the electrical device being controlled.

Trap A fitting or device that provides a liquid seal to prevent the emission of sewer gases without materially affecting the flow of sewage or wastewater through the trap.

Valve A fitting that is used to control the flow of fluid or gas.

Vent Pipe A vertical pipe installed to provide circulation of air to and from any part of the drainage system.

Water Closet A water-flushing plumbing fixture, such as a toilet, that is designed to receive and discharge human excrement.

Water Distributing Pipe

A pipe that carries water from the service to the point of use.

Water Heater Any heating appliance or equipment that heats potable water and supplies such water to the potable hot water distribution system.

Water Meter A device used to measure the amount of water that goes through the water service.

Water Service The pipe from the water main or other supply to the water-distributing pipes.

Watt A unit of measure of power

Utilities: Utilities for any project represent a significant portion of the cost of the project. Proper layout and sizing of equipment are essential for keeping costs in check. Designers attempt to keep utility lines as short as possible because of the high cost of long lines. For example, the service wire for electrical service must be unbroken from the tap point to the panel box with no splices allowed. If four hundred feet of #0000 wire is ordered and it is four feet short, the entire cable must be replaced.

Many environmental and aesthetic concerns must also be considered when placing utilities. Wires, transformers, poles, and pipes are unsightly and are prone to weather damage. Underground utilities are expensive to install and maintain and must be protected from freezing temperatures and vehicles traveling above. When utilities are installed, wetlands and wildlife habitats must be protected.

Wastewater Management: As urban centers grew in size, it became apparent that dumping raw sewage into streets, creeks, rivers, and lakes ultimately threatened the drinking water supply. The concept of wastewater management was born.

Once water has entered a structure, it is inevitable that the water will be used and the quality changed – usually for the worse. The used water is called wastewater. The constituents (impurities) within wastewater are dependent upon how the water has been used.

Sanitary wastewater is generally accepted to consist of human waste, household cleaning solutions, oil and grease from cooking activities, small solid particles from garbage grinders, or soil from cleaning clothes and floors. Wastewater from commercial establishments may include metals, strong acids and bases, cleaning solvents, oil and grease, and grit (small plastic, glass, stone, or metal particles), in addition to sanitary wastewater. Sometimes water is used for cooling purposes; thermal pollution is created and must be managed correctly.

A civil (environmental) engineer must decide how to manage the wastewater by considering three broad categorical options:

Reuse: Wastewater that can be used again without treatment of any kind Recycling: Wastewater that is treated either on-site or off-site and used again

Discharge/treatment: Wastewater that is simply discharged from the structure for treatment either on-site or off-site

HVAC

HVAC plans show the size and location of the equipment, ductwork, and components of the system. Often the plans include notes, schedules, and specifications. This is a partial HVAC drawing.

Here the air handling units (AHU) have been shaded red, the supply ducts have been shaded green, and the return ducts have been shaded blue. Notice that the air flows are also noted in cubic feet per minute (CFM). All of the tags refer to specific component descriptions found in schedules within the drawing set.

Lesson 3.4 Site Considerations - OverviewPrefaceYou may not notice the design of a site unless problems exist. As long as there is an empty parking space when you visit a business, there are sidewalks to provide a level walking surface, handicapped access for the disabled, and the pavement is passable during heavy rain, you may take the site design for granted. These days, landscaping is also often overlooked unless it is lacking. The goal of site design is to enhance the project with the least disruption to people and the environment; so, the site design may go unnoticed. However, a civil engineer must carefully plan site elements in order to achieve a good design.

To make the best use of a site, civil/site engineers must consider many factors and balance the use of manufactured elements with natural features. Vehicular and pedestrian traffic should flow smoothly and safely, adequate parking should be available, and storm water should flow away from the building and be quickly diverted to storm water facilities. If all of these systems are coordinated with the building design and the needs of the users and client are addressed in an attractive and environmentally friendly way, the site design is successful.

In order that these systems operate as intended, engineers and architect need information about the site on which to base the design and inform the construction. For example, an accurate point of reference to provide a correct elevation on the site is necessary in order to construct the building and properly grade the property. Information on the characteristics of the soil is needed in order to properly design the structure, pavements, and drainage system.

In this lesson, students will perform land surveys and soil analyses to gather necessary information. The remainder of the unit will guide students in the site design for the Keystone Library Renovation Project. The intent is that each student will design an attractive site to enhance the Keystone Library building and provide efficient parking, traffic flow, and storm water management with minimal impact on people and the environment.

Understandings

1. Land surveying is used for many purposes during the design and construction of a project, including establishing the topography of a site, setting control points, and establishing the location of project features.

2. Engineers must consider parking requirements, pedestrian access, ingress and egress, landscaping, storm water management, and site grading when creating a site design.

3. Ingress and egress, parking, pedestrian, and handicapped access must be planned to efficiently and safely move traffic, goods, and people.

4. The characteristics of soils present on a site impact the design and construction of improvements to a property.5. Codes determine the type, sizing, and placement of site features such as parking lots, entrance and exit roads,

pedestrian and handicapped access, and storm water facilities.6. The surface conditions and topography of a site affect the quantity and quality of storm water runoff and the design of

the storm water management system.7. A soil can be classified according to its grain size and plasticity which impact the characteristics the soil will exhibit.

Knowledge and SkillsIt is expected that students will:

Use differential leveling to complete a control survey to establish a point of known elevation for a project. Design appropriate pedestrian access, vehicular access, and a parking lot for a commercial facility. Analyze a site soil sample to determine the United Soil Classification System designation and predict soil

characteristics important to the design and construction of a building on the site. Explain the impact of site development on storm water runoff. Estimate the increase in storm water runoff from a commercial site and create a preliminary design for a storm water

storage facility. Identify and explain the purpose of Low Impact Development techniques in site development. Apply Low Impact Development techniques to a commercial site design reduce the impact of development on storm

water runoff quantity and quality. Follow specifications and codes during a design process. Given 3D architectural design software, document a commercial site design.

Essential Questions

1. How is land surveying used in the development of a building project?2. What information is important to consider when planning the placement of driveways, parking spaces, and pedestrian

access?3. How are the needs of a site user and the circulation patterns for the site interrelated?4. Why is it important to know the soil characteristics of a site when planning a building project?5. How does development change the characteristics of a site?6. What steps must be taken to ensure that the improvements made on a property will not adversely affect users or

neighboring properties?

7. Lesson 3.4 Site Considerations - Key Terms

Term Definition

Angle of Repose The maximum angle of a stable slope of a granular material determined by friction, cohesion, and the shapes of the soil particles.

Backsight The reading on a rod held at a point of known or assumed elevation.

Bench Mark (BM) A relatively permanent object, natural or artificial, bearing a marked point whose elevation above or below the adopted datum is known or assumed.

Closure Error The difference between a measured or calculated elevation and the true or established elevation.

Coarse Grained Soil Soil in which 50 percent or more, by weight, of the soil is retained on the Number 200 sieve. In other words, 50 percent or more of the sample is composed of sand and/or gravel.

Construction Survey A land survey that provides points and elevations for building civil engineering projects. Often called engineering survey.

Control Survey Survey that establishes a network of horizontal and vertical monuments that serve as a reference framework for other surveys.

Datum Any surface to which elevations are referred (for example, mean sea level).

Design Storm A selected storm event, described in terms of the probability of occurring once within a given number of years, for which drainage or flood control improvements are designed and built.

Detention Pond (Dry Pond) A pond that collects storm water, temporarily stores, and then slowly releases the water into the municipal storm water system.

Differential Leveling The process of determining the difference in height between a plane of sight and a point.

Duration The period of time over which rain is measured. For example in the case of annual rainfall measurements, the duration is one year.

Egress Exit or a way out.

Elevation The vertical distance from a datum to a point or object.

Field Notes A complete record of all measurements made during the survey with sketches and narration, where necessary, to clarify the notes.

Fine Grained Soil Soil in which more than 50 percent, by weight, of the soil passes the Number 200 sieve. In other words, more than 50 percent of the soil is composed of silt and/or clay.

Finish Grade The final elevation of the ground surface after excavating or filling.

Foresight The reading on a rod held at a point whose elevation is to be determined.

Geodetic Survey Surveys to determine relative positions of widely spaced points which require consideration of the size and shape of the Earth.

Grading The process of changing the topography of a property for a purpose.

Height of Instrument The vertical distance from the datum to the line of sight of the instrument.

Impervious Incapable of being penetrated.

Ingress Entrance or means to enter.

Initial Point The starting point for a survey.

Land Surveying The science of determining relative positions of points on or near the Earth’s surface.

Liquid Limit The minimum moisture content, expressed as a percentage of the oven dry soil weight, at which the soil will begin to flow when subjected to a small shearing force. The liquid limit is determined using a standard liquid limit device.

Low Impact Development A storm water management approach that uses green space, native landscaping, and techniques that mimic a site’s pre-development water cycle.

Plane Survey Surveys for which the curvature of the Earth is ignored and measurements are treated as if taken on a plane surface.

Plastic Limit The minimum moisture content at which the soil can be rolled into a thread one-eighth of an inch in diameter without crumbling and is determined by trial and error.

Plasticity Index The difference between the liquid limit and the plastic limit.

Poorly Graded A soil that does not contain a good representation of all particle sizes. A poorly graded soil may contain a narrow range of particle sizes (uniformly graded) or may not contain one or more ranges of particle

sizes (gap graded).

Property Survey A land survey that establishes property corners, boundaries, and areas of land parcels. Also called land surveys, cadastral surveys, and boundary surveys.

Rainfall Intensity The ratio of the total amount of rain (rainfall depth) falling during a given period to the duration of the period.

Retention Pond (Wet Pond) A permanent on-site pond used to manage storm water in which pollutants are allowed to settle out or be removed by biological activity.

Return Period The length of time, on average, over which an event (or an event of greater magnitude) is expected to occur not more than one time. For example, a Category 3 hurricane may have a return period of 100 years, which means that a Category 3 hurricane (or stronger) is expected to occur no more than one time, on average, within one hundred years.

Rod Intercept The difference between the rod readings at the stadia wires.

Runoff Coefficient A number that indicates the portion of rainwater that will be discharged by a particular surface.

Stadia Two horizontal cross wires that are equidistant from the center crosshair in the sight.

Storm Water Wetlands A permanent shallow pool of diverted rainwater that incorporates wetland plants. Pollutants are removed through settling and biological activity.

Topographic Survey A land survey used to prepare maps showing location of natural and man-made features and elevations of points on the ground.

Well Graded A soil that displays a good representation of all particle sizes. For instance, well-graded sand will contain a fairly even distribution of coarse, medium, and fine sand.

Accessible car spaces must be at least 96 inches wide, and accessible van spaces must be at least 132 inches wide. Each accessible space must be adjacent to a 60 inch wide aisle on an accessible route to the building

Soil testing allows the engineer to determine how the soils will behave as a construction material. Soils classification determines the various physical properties of the soil and provides a correlation to the engineering properties.The soils underneath a building will influence the type and size of the building foundation. In turn, the foundation may influence the type of building structure that will be erected. The soils conditions can also affect the construction costs. The bearing capacity is the ability of the soil to carry the load without any failure within the soil. It is also referred to as the stability of the soil. The load-carrying capacity of the soil can vary with the strength of the soils and the method and magnitude in which the loads are applied.

The amount and rate of settlement of the foundation can be estimated for a known soil type, and the building can be designed to accommodate a certain amount of settlement.Earth pressure refers to the pressure that the earth transmits to the building.The drainage qualities of the soils can affect the pressure on the foundation with excessive water pressure.

The Unified Soils Classification System is a rapid method for identifying and grouping soils. It was first developed by Casagrande for military construction of airfields.Many soils can be grouped visually with the USGS. Additional tests for grain size and plasticity are required to accurately classify the soil.

The plasticity chart can help distinguish among the fine-grained classifications of clay and silt. Once the LL and PI are determined, a point is plotted on the chart. The classification is indicated by the region in which the point falls on the chart.

Low Impact Development (LID) techniques have been developed to address storm water quantity and quality issues by more closely imitating the natural hydrology of a site. Many communities are now encouraging engineers to incorporate LID techniques in site design to reduce the negative effects of development on the quantity and quality of storm water runoff. In addition, LID often improves visual and sensory aspects of the design by creating a greener design than traditional site design.