bme Ép.szerk.tanszék fire protection features of slabs

fire protection features of slabs

examples:

- covered beam timber floor: D, REI 45

- dowelled beam timber floor: D, REI 60

- Cambered arch vault (HR steel beam + brick vault): A1, REI 15 – REI 30

- E beam floor with concrete filler block, plastered: A1, REI 45

- monolithic RC slabs (depending on dimensioning): A1, REI 30- REI 120

fire protection requirements 2

requirements for floors 13 - fire protection

© Becker Gábor 2017BME Ép.szerk.Tanszék

additional - special - requirements:● harmonization of different floor structures and coverings

● floor slabs for dynamic loads (large-section garage slabs with bottom ribs, coffered ceiling)

● floors against electrostatic charge (conductive floor coverings connected to grounding grid)● transparency-opaque requirements (glued safety glass slabs)

special requirements

requirements for floors 13


wire installation requirements

● building pipelines (heating, electric, weak current) can be integrated in the floor structure only if they are qualified for this purpose (e.g. multilayer high

pressure plastic or soldered copper pipes)

● sewage pipes and water pressure lines should not be run in slabs or floors above any room with long-term stay function!

sewage pipe MUST NOT be run in slabs

or floors!

sewage pipe in insulated floor channel

heating pipes and electric wiring

sewage pipe in conduit

possibility of wire installation



*

possibility of wire installation



monolithic reinforced concrete floors

history: - with the introduction of concrete technology, since the early 1900s

- initially between steel beams, constructed as bottom or top ribbed slabs


● constructed on site, concrete pouring after formwork preparation and reinforcement

laying

● material: concrete (due to the curved structure with C16, C203.C30 class, where

"C" means the 28-day strength of the concrete, 16, 20330 N/mm2

● advantage: homogeneous material, robust co-working structure, good

soundproofing, ensuring multiple-support, favourable cross-sectional ratios

● disadvantage: high self-weight, expensive formwork, relatively long construction

time

reinforcement during placement formwork during installation

monolithic floors 1floors - reinforced concrete floors

type of monolithic reinforced concrete floors

flat floor


bottom-ribbed floor

waffle slabtop-ribbed floor


mushroom slab (with mushroom head)

© Becker Gábor 2017BME Ép.szerk.Tanszékmushroom floor with top-to-bottom flat

surface ("hidden mushroom")


floors with closely placed ribs and ceramic elements

● dense, reinforced concrete ribs between the co-working loadable blocks

(notched, ribbed side surface)

● increasing the compressed zone with concrete overlay

● increasing the positive moment with breaking out the rib of the block

● best known is the Bohn type slab (burnt fireclay)


lightened monolithic RC slabs

hollow block monolithic RC slab bubble deck slab recycled plastic

concrete saving monolithic floors 1floors - reinforced concrete floors

beam-fillerblock floors● mass construction demand, development of the building industry and prefabrication

● introduction of size co-ordination and typization


● consisting of load-bearing beam and fillerblocks for transferring and distributing loads

● one-way, two-support beams (partially restrained)

● full load-bearing capacity is achieved after the concrete between the blocks and beams

or the overlay concrete is hardened

by the extent of prefabrication they can be:

● prefabricated in full cross-section

(RC beam) and

● partially prefabricated

by their reinforcement

● mild and

● pre-stressed reinforcement

beam prefabricated in full cross-section

partially prefabricated beam

concrete works

beam-block floors

RC concrete floors – prefabricated floors

concrete works


beam-block floors

RC concrete floors – prefabricated floors

design and installation (floors with beams and blocks)

supporting and over raising during construction


● during construction, the semi-prefabricated (ceramic profile) beams should be

- supported – carrying a temporary load

- over raised - reducing deflection (usually l /300)

● support

- up to 2.50-3.20 m span one,

- over 3.20 m two,

- over 4.80-5.0 m three supports

(product-specific,

see application

manuals!)

design and installation – temporary supporting

prefabricated floors - beams and filler blocks

ring beam - beam head joint

restrained beam end


sitting on the last course of brick

prefabricated beam semi-prefabricated beam

ring beam tie

reinforcement

design and installation – ring beam


beam position, ring beam connection parallel to the beams


with modulated connectionwith leveling slab

with ring beam extension placing into the ring beam

design and installation – ring beam


increasing options of load bearing capacity


beam duplication monolithic rib

denser spacing of beams (narrower filling blocks)

increased overlay concrete thickness reinforced overlay

concrete

stronger versions of floors


cross rib - stiffening rib


task: stiffening, co-working, preventing cracks

minimal ring beam on internal load bearing wall !!

number of stiffening ribs:2.00-3.75 m span - 13.75-5.75 m span - 25.75-7.00 m span - 3

(product-specific, see application manuals!)

stiffening (cross) rib, ring beam on internal load bearing wall



floor design

2.50 m span: single beam, 60 cm spacing

4.25 m span: double beam, 45 cm filler block

the plan serves only as an illustration, the right-hand floor is actually over-calculated by approx.double than needed

floor design


● load-bearing walls

● stiffening walls

● load-bearing direction

● span

● choice of structure

● (span check)

● loadb. capacity check

determining the

structure

● critical places:

openings, shafts,

partitions

● balcony, loggia

● beam arrangement

● detail plans


prefabricated beam floors

prefabricated floors - beam and hollow block floors - tensioned RC beam

beam - filler block floors

beam floors prefabricated in full cross-section

span: 2.40 - 6.60 m modular unit: 60 cmfiller blocks: spacing: 60 and 30, height: 19 and

24 cm, sign: EB 60/19

tensioned RC beam "E" e.g. E-36 = 3.60 m

(19 cm high)

Height: 24 cm

span: 3.00 - 7.20 m, modular unit: 60 cm

Filler blocks are the same






prefabricated floors - beam and filler block floors - tensioned RC beam

beam - block floors

beam floors prefabricated in full cross-section

span: 2.40 - 6.60 m modular unit: 60 cmhollow blocks: spacing: 60 and 30, height: 19

and 24 cm, sign: EB 60/19

tensioned RC beam "E" e.g. E-36 = 3.60 m

typical details of prefabricated RC beam floors



lintel cross section parallel to the beam

intermediate load bearing wall, cross

section parallel to the beam

support of partition wall

cross section of ring beam

perpendicular to the beam


partly-prefabricated beam and filler block floors

prefabricated floors - beam and filler block floors

partly-prefabricated beam and filler block floors

„Master” floor: RC beam, concrete filler block

over 6 m cross-rib is required, can also be installed

as cantilever

filler blocks: spacing: 59 (57.5) cm, height 19 cm

span: 1.20 - 8.90 m modular unit: 20 cmoverlay concrete: 4-11 cm, with reinforcing mesh

semi-monolithic: support and over lifting


semi-prefabricated beam and filler block floors

prefabricated floors - beam and filler block floors

semi-prefabricated beam and hollow block floors

semi-monolithic: support and overlifting

span: 2.25 - 7.0 m modular unit: 25 cmfiller blocks: spacing: 60 and 45 cm, height: 17 and 10 cm, sign: PTH 60/17, 45/10

overlay concrete: 4-7 cm, with reinforcing meshcross rib spacing max. 2 m, 2 pcs over 3.75 m, 3 pcs

over 5.75

Porotherm precast concrete beam in ceramic shell

advantages: easy-to plaster, modular unit matching the walling block, easy-to-shape, flexible (reinforcement, lintels), easy installation of mechanical wiring and piping Disadvantage: filler block may break during construction

filler blocks

filler blocks: spacing: 59 (57.5) cm, height 19 cm

span: 1.20 - 8.90 m modular unit: 20 cmoverlay concrete: 4-11 cm, with reinforcing mesh

„Master” floor: RC beam, concrete filler block


Porotherm floor

beam and filler block floors – semi-prefabricated floors


Porotherm and FERT floors


FERT floor


lintel cross section parallel to the

beam

middle bearing wall, cross section parallel

to the beam

cross section of crown

perpendicular to the beam

reinforcement under partition wall

typical details of semi-prefabricated RC beam floors





Floor construction stages

1. transportation

2. temporary support installation

3. placement of beam units

(balconies, shafts, etc.)

4. surmounting (over-lifting)

5. filler blocks are put in (ceramic,

concrete etc.)

6. placement of steel upper

reinforcements (eg. steel mesh)

7. placement of beam connection

steel reinforcement

8. pouring of the concrete

9. after treatment

10.support removal




Main rules at arranging beam + filler block floor constructions

1. fulfill the average load bearing requirements (depending on the

span)

2. beam must not be in the chimney wall

3. Minimum ring beam cross dimension 12 cm

4. support of special loads (For i. partition wall, monolithic area) �

arrangement (double, triple beam)

5. cross ribs to avoid buckling + load transfer

6. changing of span

7. technology of balconies � monolithic (frost-resistance)

8. support of balconies � cantilever with thermal insulation �

thermal break (see later)


hollow-core floor slabs

prefabricated floors - plank floors

tensioned RC hollow-core floor slabs

height: 6; 20; 26.5; 32; 40; 45; 50 cmspan: 3.50 – 23.50 m (!!!)

width: 120 cm (60, 90)

advantages:● plaster-free surface● large selection - slab

thickness and load bearingcapacity● large spans as well

● fast construction● can be used immediatelydisadvantages:● width is determined

● transport requires special machines

ring beam section parallel to the floor plank axis - closure of circular cavities

hollow-core floor slabs




formwork panels


formwork panel slabs

panel top view and section

slab thickness: 14-30 cm ring beam detail and rotated sectionadvantages:● plaster-free surface● good sound insulation

● variable slab thickness and load bearingcapacity

● wide range of sizes, unique forms

● easy installation of mechanical wiring and piping

● fast construction

larger openings made in plant, on site max. 20x20 cm

computer-controlled production → actually any size and shape can be produced


formwork panels



thermal break elements

prefabricated floors - floor design


consequences: discoloration (dust sitting on), condensation (dew point),

mold formation (not healthy), higher heat loss

essence of thermal bridges: multidimensional heat flow (uneven heat distribution)

cause: e.g. change of materials – different heat-conducting materials

most commonstructural: structures joining the slabs for proper static operation

(slabs, beams, balconies, loggias, canopies) doors and windows, ventilation geometric: wall corners, wall-floor corners, corners along the floor

thermal imagery of a cantilevered balcony –RC slab runs to outdoor

space without thermal break


avoiding thermal bridgesfor structures connected to the floor:

slabs: wrapping with thermal insulation or using thermal

break elementsbeams: wrapping with thermal insulation (with thermal

break elements!)

ring beam, lintels: thermal insulation placed in the formwork + thermal insulation of exterior wall

isotherms with or without thermal break elements –

balcony slab

thermal break

element



construction and typical dimensions of a thermal break element(also available with thicker – 10, 12, 16 cm –thermal insulation)

photo of a thermal break elementpress plates are painted in blue


construction of thermal break elements



cantilever slab with thermal insulation

wrap

cantilever slab with thermal break element








advantages: no need of thermal insulation around balcony(+ waterproofing), slimmer construction, quick and easy installation

disadvantage: relatively expensive, less freedom in geometry and force arrangement

cantilever

slab

two-way cantilever slab

supported on 3 sides

supported on 2 sides

the geometry of reinforcement for a variety of forces and geometries: cantilever, only sit on the wall, cantilever and sit on the wall with plane change, to attic wall etc.



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for your attention!

bme Ép.szerk.tanszék fire protection features of slabs

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