Sketch - Seismic Report

7/18/2019 Sketch - Seismic Report

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Landspitali hospital seismic a

Bedward

Treatment

Day patient



REPORT

Report nr.: Project nr.: Dato:

1 333582 26. 1

Client:

.

Landspitali hospital conceptual seismic analy

Summary:

.



Content:

1 ...................................................................Introduction2 ......................................................................Summary

3

.................................Basis for design and calculations3.1

..............................................................................Introduction

3.2

..............................................Horizontal load resisting system

3.2.1 ..................................................Ductile wall characteristics

3.2.2 ......................................................Location of ductile walls

3.3 ...................................................Response Spectrum Method

3.3.1

................................................................ Analysis software3.3.2 .............................................................................Modelling

3.3.3

........................................................Loads and load factors

3.3.4 .............................................Materials and material factors

3.4

..........................................................................Seismic action

3.4.1 .....................................................................................PGA

3.4.2

..................................................Elastic response spectrum3.4.3 ....................................................................Load directions

3.4.4

..................................................................Behaviour factor

3.4.5 .................................................................Importance class

3.5

..........................................................................Design criteria

3.5.1

.....................................................................P-Delta effects

3.5.2

...............................................Limitation of inter-storey drift

3.5.3

.......................................................Limitation of axial loads4 ..........................................................................Results

4.1 ..............................................................................Introduction

4.2 ...........................................................Maximum deformations

4.2.1 .......................................................Bed ward deformations

4.2.2

......................................................Treatment deformations

4.2.3

....................................................Day patient deformations

4.3 ..............................................................Maximum axial stress

4.3.1

..........................................Bed ward structural walls stress

4 3 2 T t t t t l ll t



Appendix:

Appendix A Bed ward

Appendix B Treatment Appendix C Day patient

Appendix D Veri ficat ion by hand calculat ions



1 Introduction

A conceptual seismic design has been carried out for the new LaHospital located in Reykjavik, Iceland.

The main objective with this work has been to choose a robust lasystem which complies with safety requirements in Eurocode 8 /

The following buildings are treated in this report:

• Bed ward• Treatment• Day patient

The building geometries have been modelled in a 3D finite elemeresponse spectrum analyses have been performed. The finite elbeen verified by hand calculations using a simplified method /2/.

All structural walls designed for seismic forces are assumed fixesuitable anchoring. Foundations are assumed to be continuous uinvestigated buildings ensuring a well distributed action from thebuildings.

2 Summary

A lateral force resisting system with ductile concrete structural winvestigated. The structural walls in the different buildings invest

with thick red lines in Figure 1, Figure 2 and Figure 3. Calculatiolayout show deformations and concrete stress which are accepta



3 Basis for design and calculations

3.1 Introduction

Basis for the design is Eurocode 8, EN1998-1-December 2004. short form when referred to in this document.

3.2 Horizontal load resisting system

All buildings considered are designed as wall-equivavalent dual distributed concrete structural walls as primary seismic membersforces are supported by columns designed as non seismic elemhorizontal forces the roof and floors are acting like diaphragms aelements towards the concrete structural walls. The concrete str

in place and continuous from top to bottom of the buildings. Ovemust be balanced by anchoring to the bed rock. A principal drawFigure 4.

m

m

Storey mass

Co

Reaction forces (red = tension and



is designed such that yielding in the reinforcement on the tensioconcrete cracks in compression on the compression side.

3.2.2 Location of ducti le walls

The location of the concrete structural walls is primarily around sand electrical shafts. Concrete structural walls are if possible plaperimeter of the building to avoid torsion modes. Additional walls

necessary by the analysis. Effort is made to meet architectural d

3.3 Response Spectrum Method

The methodology used for the structural response is a linear detknown as the Response Spectrum Method. The structural stiffnedamping are modelled in a finite element model. Then the free vcharacteristics of the system are determined and the response sperformed.

3.3.1 Analysis software

The analyses are carried out in the finite element method prograMillennium. For references see, http://www.robobat.com.

3.3.2 Modelling

All columns are modelled as continuous with fixed base and all scontinuous plates. All structural walls are modelled with thicknesstructural walls and cladding are not modelled.

All buildings are modelled fixed at the ground level. Number of sheights are given in Table 1

Table 1 Number of storeys and building height

.

Building Number of storeys Building heigths [m]

Bed ward 8 32

T 7 28



Gravity loads are evenly distributed on all floors. The values are

Table 2 Loads

Load type Value [kN/m2]

Dead load slabs1) 10.3Dead load roof 1) 8Dead load structural walls 7,5Live load 4.0Snow 0.75

1) All slabs are modelled with thickness t=300mm and remainingadded with additional load cases.

Load factors for seismic load cases are shown in Table 3

Table 3 Load factors

.

Load type Load factorDead load 1.0Live load 0.3Snow 0.2Earthquake 1.0

3.3.4 Materials and material factors

In the calculations Young’s modulus and the shear modulus for tstructural walls are reduced with 50% to account for reduced stifafter cracking. Originally and reduced values are shown in Table

Table 4 Material properties for structural walls

MaterialOriginal value [N/mm

2] Value used in calc

Concrete B30Young’s modulus 26000 N/mm2 13000

Shear modulus 11000 N/mm2 5500 N

Material factor for concrete strength is 1.0.



3.4 Seismic action

3.4.1 PGA

The seismic action is described by peak ground acceleration wit475 years, see Figure 4. The PGA chosen for the seismic design

Figure 5 Probabilistic determined PGA for Reykjavik with a return period of 475 year

3.4.2 Elastic response spectrum

The seismic action is described by the elastic response spectrumsuitable for earthquakes with magnitude < 5.5 on the Richter sca



3.4.4 Behaviour factor

The behaviour factor gives the potential reduction of forces fromspectrum analysis.

Energy dissipation level is set to medium (DCM). The behaviourcalculated according to EC8 5.2.2.2:

q = q0kw ≥ 1.5q0 = 3.0* αu/α1 αu/α1 = 1,2 wall - or wall equivalkw = (1 + α0 ) / 3 ≤ 1 , but minimum 0.5α0 ≈ hwi/lwi = 1 hwi=height of wall ankw = 0.67q = 3*1,2*0.67 = 2.41

3.4.5 Importance class

All buildings analysed are classified as importance class IV, ref. Importance factor is set to 1.4.

3.5 Design cri teria

3.5.1 P-Delta effects

Second order effects (P-Delta) is taken into account according to

Below, a check of the Day patient building with 10 storeys is perused in the calculation are from the simplified response spectrum Appendix D.

Ө = Ptot*dr /(Vtot*h) < 0.10 Inter-storey drift sensitivity coeffic

Ptot = 73.8 MN Total gravity load for seismic load



For the Day Patient building with a height of 40 m and maximummm, P-Delta effects can be neglected. Based on this result, P-D

neglected for all building types investigated in this report.

3.5.2 Limitation of inter-storey drift

Maximum allowable inter-storey drift is limited to 0.005*H were HEC8 4.4.3.2.

Example Outpatient 10 storey:

Maximum displacement in top of the structure is approximately 0

3.5.3 Limitation of axial loads

Buckling of the structural walls is associated with a non ductile fa

axial loads due to seismic forces is limited to maximum 40% of cstrength.

Axial normalised loads <0.4 ref EC8 5.4.3.4.1 (2)

4 Results

4.1 Introduction

Detailed results from the seismic analysis such as deformed geofrequencies and Eigen modes are presented in Appendix A, B a

The results most relevant for the conceptual design are shown insections.

4.2 Maximum deformations

The maximum deformations for each structure in the two princip



All calculated deformations are within the limits given in EC8.

4.2.1 Bed ward deformations

Figure 6 Maximum deformations with dominating x directional earthquake



Figure 7 Maximum deformations with dominating y directional earthquake



4.2.2 Treatment deformations




4.2.3 Day patient deformations





4.3 Maximum axial stress

Maximum axial concrete stress due to seismic loading is shown Table 6

Table 6 Maximum normalized vertical load

and compared with maximum allowable concrete stress

Structure Concrete stress [Mpa] Limit [M

ConcreteHorizontal dir. Vertical dir.

26.242) 8.89 9.52Bed ward

26 012)10 88 9 52Treatment



4.3.1 Bed ward structural walls stress

Figure 12 Vertical concrete stress with dominating x directional earthquake



Figure 13 Vertical concrete stress with dominating y directional earthquak



4.3.2 Treatment structural walls stress

Figur e 14 Vertical concrete stress with dominating x directional earthquake



Figure 15 Vertical concrete stress with dominating y directional earthquake



4.3.3 Day patient structural walls stress

Figure 16 Vertical concrete stress with dominating x directional earthquake



Figure 17 Vertical concrete stress with dominating y directional earthquake

5 Verification by hand calculations

5 1 Introduction



Details from the simplified analysis is given in Appendix D.

5.2 Results

Table 7 Comparison of results from simplified analysis and finite element

Results simplified

analysis

Results

a

Dynamic mass 7681 tonnes 75

1.Eigen frequency 1,25 Hz 1.Eigen period 0.8 s Maximum displacement 50 mm Base shear 9.2 MN 1Global seismic moment 238 MNm 2

The results in Table 7 show that the simplified method gives 14%and 18.4% higher global moment compared to the finite elementreasonably accurate for a simplified analysis which is primarily mbase shear. The calculations of dynamic properties show large delement model gives a more correct prediction of the dynamic prto higher accuracy of the stiffness in the model.

From this verification we find good agreement between global fo

simplified method and the finite element analysis.



6 References

/1/ Eurocode 8, EN1998-1-December 2004 /2/ Norwegian code NS3491-12 Design actions Part 12: Seismic actions

Sketch - Seismic Report

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