EPU (ESA-Punching)

MANUAL

SCIA

Scientific Application Group

________________________________________________________________________ Release : 3.50 Module : EPU.01 Manual : EPU Revision : June 2002 ________________________________________________________________________ SCIA Group n.v. Scientific Application Group Industrieweg 1007 B-3540 Herk-de-Stad (België) Tel.(+32) (0)13/55 17 75 Fax.(+32) (0)13/55 41 75 E-mail scia@scia.be ________________________________________________________________________ SCIA W+B Software b.v. Postbus 330 NL-6860 AH Oosterbeek (Nederland) Tel.(+31) 26-3338008 Fax.(+31) 26-3341949 E-mail scia@scia.nl ________________________________________________________________________ SCIA sarl Parc Club des Prés Rue Papin, 29 - F-59650 Villeneuve d'Asq (France) Tel.(+33) (0) 3.20.04.10.60 Fax.(+33) (0) 3.20.04.03.36 E-mail scia@nc.net.tm.fr ________________________________________________________________________ SCIA Software Gbr Emil-Figge-Str. 76 Gebäude I Tel.(+49) 231/9742586 Fax.(+49) 231/9742587 E-mail scia@scia.de

ABOUT THIS MANUAL The following conventional text formats and symbols are used throughout this manual : Convention Meaning

bold

Indicates texts used in the program (menus, texts in dialog windows, buttons, etc.). E.g. Enter the length of the beam in the Length field.

[between brackets] Indicates a button. E.g. Click on [OK] to confirm.

Italic text Indicates a procedure to follow to execute this operation. E.g.

To change the properties of ...

1. Step 1 2. Step 2

Indicates the different steps in a procedure. Each step describes one action. E.g. 1. Enter the value in the Coefficient field. 2. Click on [OK] to confirm.

Menu > Submenu Indicates items and subitems from the main menu (on top of the screen) or from the menu tree (left side of the screen). E.g. ... choose Setup > Options from the main menu.

Information in this document is subject to change without notice. No part of this document may be reproduced, stored in a retrieval system or transmitted, in any form or by any means, electronic or mechanical, for any purpose, without the express written permission of the publisher. SCIA Software is not responsible for direct or indirect damage as a result of imperfections in the documentation and/or software. Copyright 2002 SCIA Group. All rights reserved.

TABLE OF CONTENTS

INTRODUCTION ............................................................................................................................ 3 MAIN INTERFACE ......................................................................................................................... 4 PUNCHING CALCULATION........................................................................................................... 6 THE PUNCHING MENU ................................................................................................................ 18 TUTORIAL................................................................................................................................... 22 EXAMPLE..................................................................................................................................... 22 THEORETICAL BACKGROUND................................................................................................... 29 EC................................................................................................................................................ 29 NEN............................................................................................................................................. 34 BS................................................................................................................................................ 37

Manual EPU

INTRODUCTION

Welcome to the Single Punching Module (EPU) manual. This program is a stand alone part of ESA-Prima Win (EPW), a designing and analysing program under Windows 95/Windows 98/Windows NT/Windows2000/WindowsXP with a wide range of applications: from control of simple frames to advanced design of complex projects in steel, concrete, timber, ... This manual is specifically made for the stand-alone module for the punching calculation and the design of punching reinforcement. Experienced users of ESA-Prima Win immediately recognise the look of the EPU program. As a fact EPU is subtract of the EPW program and uses the same functions as EPW. EPU however is meant for 'basic' punching calculations only, EPW is capable of making punching calculations using the dimensions, properties and results as defined or calculated in EPW. Since EPU uses the same functions as EPW for some parts of the program this manual will refer to the EPW manual. Especially the part concerning the 'general' interface, like printing, units set-up, workspace, etc. will not be discussed in this manual. For these items the user should refer to the "ESA-Prima Win Reference manual" and the "ESA-Prima Win Reinforced concrete manual". Most functionality in the modules depends on national codes. The following national codes are available within EPU : Eurocode 2 DIN 1045-1 DIN 1045 7/88 SIA 162 BS 8110 NEN 6720 ONORM B 4700 (beams and columns) CSN 731201 STN 73 1201 BAEL 91

In the first part the interface of the program is described. In the second part the punching calculation is described. In the third part the punching menu is described. In the fourth part an example calculation is given. As an appendix a theoretical background is given.

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MAIN INTERFACE

After the initiation of the program, the user must press the [ ] button to start a new punching calculation. Then the user is asked to set the values for the national codes, units and concrete class. Additionally the user can set project specific text, etc., see figure:

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After pressing the [OK] button, the following screen is depicted:

The menu tree consists of the following branches 'Punching' and 'Document'. In the document all calculations that the user send to the document have be stored, see EPW manual. In the 'Punching' branch the punching calculation and design of punching reinforcement is performed. Double clicking on the 'Punching' branch starts the punching calculation.

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PUNCHING CALCULATION

The punching component consists of the following tab sheets. - Geometry of punching - Main reinforcement - Loads - Design of reinforcement - Doc Setup - Doc Preview They are separately threated in the following paragraphs.

Geometry of punching

The data of this tab sheet are mainly used to determine the critical perimeter.

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Description

Here the user can enter an individual description per calculation.

The Column type group

Column data The dimensions of the column can be defined in these fields. The axes in the picture are the local axes of the column. Hole data Check the 'Hole' box, if one want to define a hole. One can define circular as well as rectangular holes. In this group, the dimensions of the hole have to be defined.

The Column Position group

Column position The following column positions are available

- Parallel to the x-side - Parallel to the y-side - Corner column - Central column

The axes in the picture are the axes of the plate

- Parallel to the x-side

Column distance y Distance in the y-direction between the edge of the slab and the nearest side of the column.

Angle of edge with x-axis

Angle of the edge in respect to the local axis of the column.

- Parallel to the y-side

Analogue to parallel to the x-side

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- Corner column

Column distance y Distance in the y-direction between the corner and the nearest side of the column.

Column distance x Distance in the x-direction between the corner and the nearest side of the column.

Angle of vertical edge

Angle of the edge of the slab with the x-axis

Angle of horizontal edge

Angle of the edge of the slab with the y-axis

- Central column

No position definition is needed Hole position

If one checked 'Hole' in the Column type group, the following positions have to be defined.

Hole distance y Distance in the y-direction between the hole and the x-axis through the centre of the column.

Hole distance x Distance in the x-direction between the hole and the y-axis through the centre of the column.

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The Section group

Plate data

Thickness of the plate

Thickness of the plate at the critical perimeter.

Column head data group

Column head Check this box to define a column head. For rectangular columns one can only define rectangular heads. For circular columns one can define both circular as well as rectangular heads.

prismatic pyramidal cylindrical conical

Select the type of the column head. Prismatic and Pyramidal are for rectangular columns, cylindrical and conical are for circular columns

Column head measurements

Depending on the column head type the depth and width of the column head can be defined using the appropriate fields.

The Material group

[Concrete] Click this button to change the material quality of the slab. The Actual Material dialog box will appear.

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Loads

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For each loadcase/combination, selected in the Concrete > plates, walls , shells > punching menu, the loads / internal forces are shown.

Qd Distributed load (2D) on the slab of the appropriate loadcase/combination

← Input > Loads > Distributed loads 2D.

It is used to correct Vd → punching force VSd_punch (see theoretical background).

Vd Concentrated load, causing the punching force. For a support, this is the reaction force. For a column, it is its normal force that works on the slab.

Mxd Bending moment per unit length in the x-direction in the slab for the appropriate loadcase/combination.

← Results > 2D forces - 'in nodes' This moment is only used the check the minimum design bending moments.

Myd Bending moment per unit length in the y-direction in the slab for the appropriate loadcase/combination.

← Results > 2D forces - 'in nodes' This moment is only used the check the minimum design bending moments.

For the convention of the signs, see the picture in the tab sheet.

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Main reinforcement

This tab sheet determines the longitudinal reinforcement amount in the plate near the node that is considered. Profile group, Angle group and Material group The same groups as in the levels of reinforcement dialog box (Concrete > plates, walls , shells > input - [Reinforcement] ). See the appropriate part in the concrete manual for more information about these fields.

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Distance group In the fields in this group the distances between the longitudinal bars in a layer are shown. Area group In this group, the areas per unit length for the corresponding layer are shown.

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Design of reinforcement

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Loads (Case/Combi) group In the list box, one can select one of the cases/combinations that were defined in Tab sheet Loads. For this loadcase/combination, the results of the punching control are shown. Critical section group For each code the important values are shown. See the theoretical background for more explanation on how the following values are calculated. [Calculation] Click on this button to perform a calculation when values are manually changed.

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Doc Setup

In this tab sheet, one can define the document setup of the preview and numerical output to document or printer.

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Doc Preview

In this tab sheet, a preview is given of the results of the punching control of the appropriate node.

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THE PUNCHING MENU

After pressing [OK] the user enters the following dialogue.

In this dialogue the user manages the number of punching calculations in this project by deleting, editing, printing, etc.

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Calculation group In this group the user can copy and edit the punching calculations as shown in the list box.

[New punching] This button starts a new punching calculation.

[Edit punching] This button edits an existing punching calculation. Select the appropriate calculation in the list box first.

Delete group In this group the user can delete one or all punching calculations.

[Delete punching] This button deletes an existing punching calculation. Select the appropriate calculation in the list box first.

[Delete all] This buttons deletes all existing punching calculations.

Numerical output group

[Change of setup] This option is the same as those in tab sheet 'Doc setup' of the punching component.

[Preview All] Click this button to perform a punching calculation for all selected calculations and print the results to a preview, document, ASCII or RTF.

[Close] This button will return to the menu tree of EPU.

[Code Setup] This button will open the setup of specific code values, see figure.

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[Default settings] This button will open the dialogue with all the default settings. If the user saves his workspace in the menu bar > file > save workspace, every time a new calculation is done, these settings will be used. The 'retrieve workspace' function will retrieve the default EPU values.

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TUTORIAL

Example

Start the program. Select the flag of the NEN 6720. Select concrete class B35. Then the dialogue should look similar to the following figure:

If necessary enter a name, author and specification for the project.

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Press the [OK] button and double click on the 'Punching' branch in the EPU menu tree. Change the properties of the tabsheet 'geometry of punching' according the following figure:

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Change the values of the tabsheet 'loads' according the following figure:

Note: One can add, delete or clear a row by clicking with the right mouse button on '1', see figure:

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Change the values of the tabsheet 'Main reinforcement' according the following figure:

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Go to tab sheet 'calculation' and note the results of the punching calculation:

Set the correct steel quality by clicking on button [steel] and set it to 'FeB500'. The calculated punching reinforcement is 437 [mm2/m1]. Since the perimeter is 1.952 [m] the total punching reinforcement is 437 × 1.952 = 853 [mm2]. By clicking on the tab sheets 'section x' and 'section y' one can review the sections, see figure:

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Section x

Go to the tab sheet 'Doc Setup' and select 'detailed'. Press on button [unselect all] and tick the following options: 'results of calculation' and 'ground plan'. Go to 'Doc Preview' tabsheet and note the following output:

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Press the button [OK] and press the button [preview all] and select the option 'preview + print'. The output should look similar to the following figure:

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THEORETICAL BACKGROUND

In this paragraph, the different aspects of the control of punching shear resistance in EPU are described.

EC

Shape of the loaded area

A check is performed whether the loaded area is within the limits of EC § 4.3.4.2.1.(1).a. The parameters of this check can be modified in the setup > concrete menu, tab sheet 'punching settings'.

Determination of the critical perimeter

The critical perimeter depends on the loaded area and the plate thickness as described in EC § 4.3.4.2.2 (1).

1.5 d

1.5 d

Near openings or edges, this critical perimeter has to be decreased. The rules as described in EC § 4.3.4.2.2 (2) and (3) are applied.

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1.5 d

1.5 d

Checking punching shear - first critical section

The following conditions have to be met Slabs without punching shear reinforcement vSd < vRd1 Slabs with punching shear reinforcement vSd < vRd2 vSd < vRd3

Min. plate thickness (EC § 4.3.4.5.2 (5)) ← Setup > Concrete - Tab sheet 'Punching settings'

Min. shear reinforcement amount (EC § 4.3.4.5.2 (4)) ← Setup > Concrete - Tab sheet 'Punching settings'

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Calculation of vSd

u.βV

v Sd_punchSd =

VSd_punch See reinforced concrete manual, Punching, the punching component, Design of reinforcement, Loads (case/combi) group: Vd of the appropriate loadcase / combination qd of the appropriate loadcase / combination

Beta Setup > concrete - tab sheet 'Punching settings'

u The calculated critical perimeter See reinforced concrete manual, Punching, the punching component, Geometry of punching.

Example for calculation V Sd_punch

V d = 90 kN

q d = -10 kN/m2

V Sd_punch = 90 - 10 * A crit So Vd is decreased by a loading qd within the critical area. The contact stresses within the surface of the cone (as in EC § 4.3.4.3 (4)) are not taken into account.

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Calculation of vRd1

).d40.ρ.k.(1.2τv lRdRd1 −=

τ Rd Determined by the concrete quality.

k 1.6 - d ≥ 1.0

ρ l See reinforced concrete manual, Punching, the punching component, Main Reinforcement

d See reinforced concrete manual, Punching, the punching component, Geometry of punching (Thickness plate) and Main reinforcement (Covers, diameters)

Calculation of vRd2

Rd1Rd2 coeff'.v'v =

'coeff' Setup > concrete - tab sheet 'Punching settings' 'Coefficient for vRd2'; default 1.6

Calculation of vRd3

∑+=u

sinαfAvv ydswRd1Rd3

Asw (Calculated) punching shear reinforcement amount

fyd See reinforced concrete manual, Punching, the punching component, Main reinforcement (steel quality) and Setup > concrete (Safety factor)

α See reinforced concrete manual, Punching, the punching component, Design of reinforcement

u The calculated critical perimeter

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Checking punching shear - More critical sections

As long as the critical section considered needs punching shear reinforcement, an analogue punching check has to be performed for the next critical section.

Minimum design moments

'To ensure that the punching shear resistance can develop, the slab should be designed for minimum bending moments per unit width' (EC 2 § 4.3.4.5.3 (1)). The following conditions should be met

mRdx ≥ max ( limit mSdx , mSdx orig. )

mRdy ≥ max ( limit mSdy , mSdy orig. )

mRdx Resistant bending moments per unit length in the x-direction. See reinforced concrete manual, Punching, the punching component, Main reinforcement (reinforcement)

limit mSdx Limit design bending moment per unit length in the x- direction = 'η . V Sd'

η ← Setup > Concrete - Punching settings ('Coefficients')

mSdx orig. Design bending moments per unit length in the x-direction See reinforced concrete manual, Punching, the punching component, Design of reinforcement, Loads (appropriate loadcase / combination)

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NEN

The shear punching calculation in EPU is performed according to the NEN 6720 code. Only additional information and some remarks to the calculation routine are given in the next topics.

Check criteria

The first check perfomed during the shear punching calculation is concerning the al/ab ratio of the loaded area. For rectangular loaded areas having a ratio al > 3 ab a shear force calculation is done according NEN6720 art. 8.2.

The absolute maximum value for τ2 can be altered in the Setup for concrete dialogue, tab sheet Punching settings.

Design value of the shearforce

The used forces (Vd, Mx, My) to determine τd, which are shown in the Loads tab sheet, can be checked in the Results > Member forces menu. For each periphery the design shear force is calculated. At first instance the perimeter is considered for a mid column. However, if the distance from the c.g. of the loaded area to the edge of the slab (ar) is smaller than a 0.25 times the perimeter or 0.375 times the perimeter then it will be considered as a edge column, corner column respectively. Hence the following situation can occur:

Possible perimeters in a punching check calculation The eccentricities ex and ey are determined parallel to to main axis of inertia of the periphery. For corner columns this implies that the moments found in linear analysis have to be rewritten. To determine the eccentricities as shown in the figure below, the linear analysis moments are rewritten as follows:

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Mdy = -Mx· cos α + My·sin α

Mdx = Mx·sin α + My·cos α

α = π /4 (in normal circomstances) ex = Mdx / Nd ey = Mdy / Nd

The values for the factors αx and αy, used in determination of the eccentricity factor, are calculated according the tables 30 to 34 including. Values which are not mentioned in the table are linear interpolated.

Calculation of tau1

The value of tau1 is determined in two steps, i.e. in the first step tau1 is calculated with the equation as mentioned in art. 8.3.3 with a minimum of 0.8*fb. Although the minimum value for tau1 (0.8*fb) can be altered in Setup for Concrete tab sheet Punching settings. In the second step tau1 is multiplied with k1 and k2 if the geometry of the column requires this.

Calculation of Asv

As long as τd > τ1 τs and Asv will be calculated. The maximum number of peripheries that will be considerd is 10. Default the angle between the punching reinforcement and the suface of the slab is taken as 90°. In the tab sheet Design of Reinforcement in the Punching dialogue this value can be altered.

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Column heads acc. NEN

In cases of column heads two situations are distinguished. In the first situation (ak ≤ hk) the first section is taken at 0.5 × d from the face of the column head. In the second situation also section within the column head should be checked. The picture below illustrates the location of such a section. It is 0.5 × (d+hk) beyond the diameter of the loaded area (a) at each side in both directions.

Location of critical section in case of column head where ak ≥ hk

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BS

The shear punching calculation in EPU is almost exactly according BS8110 code. Therefore only additional information and some remarks are given in the next topics.

Location of perimeter

Depending on the choice made in Setup for concrete > tab sheet Punching settings the first critical section will be taken at 1.5d or 0.75d from the face of the column. Default the distance lp of the first perimeter is set at 1.5d. If the requirement υc < υ <2υc is still valid after this first check other perimeters are checked. They are taken at distances which are a multiple of 0.75d beyond the first perimeter.

Calculation of Veff

The BS mentiones two ways to calculate Veff; the first one uses the transmitted moment to determine Veff (equation 25 and 26) the second is a simplyfied method as it uses a mutiplication factor to determine Veff. Both methods are implemented in ESA-Prima Win. In the Setup of concrete, tab sheet Punching settings the appropriate method can be chosen. The used forces (Vt, Mt) to determine Veff, which are shown in the Loads tab sheet, can be checked in the Results > Member forces menu.

Maximum design shear capacity υmax

cu8. f0The maximum design shear stress is restricted to the lesser of and 5 N/mm2 or is limited by the provisions for shear reinforcement (υc < υ < 2υc). The minimum of all these values is used as maximum design shear capacity in ESA-Prima Win. If exceeded a message will be given.

Design concrete shear stress υc

To calculate υc the equations as mentioned in table 3.8 of BS8110 are used. For this only the reinforcement crossing the perimeter is effective. Therefore only the reinforcement crossing the perimeter is taken into account when detemining υc.

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Column heads acc. BS

For column heads it is not exactly clear where the first critical section should be taken. However, comparing the punching check calculation to other norms (e.g. EC2 and NEN6720) a good approach can be made. The BS is rather clear about the effective dimensions of a column head (BS8110 – 3.7.1.3). These dimensions are the basics for determine the first critical section. Mainly two different situations can be distinguished, i.e.: 1. lho < lh max

In these situations the first critical section is taken at 0.75/1.5 * dslab of the effective dimensions of the column head. So only sections in the slab are checked.

Situation ii and iv of Figure 3.11 of BS8110 and their 1st critical section

2. lho > lh max

In these situations it can be interesting to check sections inside the column head also. Esa Prima Win checks sections inside the column head when the section at 0.75/1.5*(dhead + dslab) of the column falls inside the real column head dimensions. In such situation the section section is taken at 0.75/1.5*(dhead + dslab) + 0.75*dslab of the column.

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Situation i and iii of Figure 3.11 of BS8110 and their 1st, 2nd critical section

If the section at 0.75/1.5*(dhead + dslab) of the column falls outside the column head, only the sections as mentioned in 1 are considered.

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