Seismic Fortification and After-UtilizationSeismic Fortification and After Utilization of Beijing Olympic Stadiums

Miao HanMiao Han

（Beijing University of Civil Engineering and Architecture Beijing 100044 PRC（Beijing University of Civil Engineering and Architecture, Beijing 100044, PRC

E-mail, hanmiao@bucea.edu.cn）

Seismic Fortification and After-Utilization of Beijing Olympic Stadiums

I. Brief introduction of Beijing Olympic Stadiums

A h 60 di f i i d i i f Among more than 60 stadiums for competition and training for the 2008 Beijing Olympics, more than 40 of them are retrofitting and renovation projects. The ages of the 40 stadiums are different, therefore the design levels of which are different.

Among the 31 stadiums in Beijing, there are 12 newly-built stadiums, 11 improvement stadiums and 8 temporary stadiums.

II. The seismic fortification of newly-built stadiumsSeismic fortification criterion for the newly-built stadiums was set up in accordance with the Chinese <Code for seismic design of b ildings> (GBJ50011 2001)of buildings> (GBJ50011-2001).

1. Classify buildings by building importance A grade building: Important constructions, the ones that may

give rise to serious secondary disasters, i.e. nuclear power stationstation.

B grade building: The service function of these buildings should not be interrupted and the buildings need to beshould not be interrupted and the buildings need to be restored as soon as possible. Such as lifeline engineering.

C grade building: General buildings beyond A B and D grades C grade building: General buildings beyond A, B and D grades, including a large number of general industrial and civil buildings.buildings.

D grade building: Secondary anti-seismic constructions.

2. Design criteria(1) Most of the newly-built Olympic stadiums belong to the B

grade building group.g g g p

(2) The design criteria of B grade buildings are as follows:

Earthquake action should meet the requirements of the local earthquake fortification intensity regulations.

In general, when the seismic fortification intensity is between 6 and 8, the seismic-protection measures should increase one degree higher than the seismic fortification intensity for that area.

2. Design criteria

(3) Beijing’s design intensity is magnitude 8. The design of the Olympic stadiums should meet the following regulations.Olympic stadiums should meet the following regulations.

The intensity of earthquake action calculation is magnitude 8.

The intensity of seismic-protection measures is magnitude 9.

(4) The design intensity is the intensity at which the probability(4) The design intensity is the intensity at which the probability exceeds 10% within 50 years.

3. Response spectrum for design

The seismic influence coefficient in the response spectrum for design has a relationship with design intensity, site g p g y,classification, seismic design group, structural natural period of vibration and damping ratio.p g

2max

Tg

0 45

max2

T

g

0.45max max12 52.0 gTT

T(s)6.0Tg0.10 5Tg

The curve of seismic influence coefficient

In the curve above Damped exponential in the descending section

05.090

The descending slope adjusting coefficient 1 in the descending

55.0

9.0

section of the straight line 805.002.01

Damping regulatory coefficient 2

05.01

Note, when 1<0, takes 1=0

7.106.0

12

when 2<0.55, takes 2=0.55

Table1 Horizontal seismic influence coefficient Table1 Horizontal seismic influence coefficient max

Design intensity

Seismic infl ence 6 7 8 9Seismic influence 6 7 8 9Frequently occurred

earthquake 0.04 0.08（0.12） 0.16（0.24） 0.32 qRare occurred

earthquake -- 0.50（0.72） 0.90（1.20） 1.40

Table2 Characteristic period Tg Site classificationDesign seismic Site classificationDesign seismic

group I II III IV Group1 0 25 0 35 0 45 0 65Group1 0.25 0.35 0.45 0.65Group2 0.30 0.40 0.55 0.75 Group3 0.35 0.45 0.65 0.90Group3 0.35 0.45 0.65 0.90

4. Design level of some newly-built stadiums

(1) The National Stadium (Bird’s Nest)

The intensity of earthquake action is magnitude 8. max=0.21

The intensity of seismic-protection measure is magnitude 9.

4. Design level of some newly-built stadiums

(2) The National Aquatics Center (Water Cube)

The intensity of earthquake action is magnitude 8. max=0.21

The intensity of seismic-protection measure is magnitude 9.

4. Design level of some newly-built stadiums

(3) The National Gymnasium

The intensity of earthquake action is magnitude 8.

The intensity of seismic-protection measure is magnitude 9. y p g

III. Seismic fortification of existing stadiums

For existing stadiums, it is unreasonable to adopt the th k ti i C d f i i d i f b ildiearthquake action in <Code for seismic design of buildings>

(GBJ50011-2001) when making the seismic assessment, i f i ’ i i i ifowing to the fact that the stadiums’ remaining working life

is shorter than the design working period.

1. Earthquake intensity distribution function and failure probability

The probability distribution of earthquake intensity of the The probability distribution of earthquake intensity of the design working period (50 years)

(1)

K

IIIIIF

exp)(

is the upper boundary of earthquake intensity. In the Chinese code, is magnitude 12.

Chinese code, is magnitude 12. is the frequent intensity, the exceeding probability is 63.2%

in a certain period. is 1.55 lower than the local designin a certain period. is 1.55 lower than the local design intensity in the Chinese code.

K is the shape parameter which can be acquired from local parameter statistics.

Table3 Shape parameter K Basic intensity 6 7 8 9

Shape parameter K 9.7932 8.3339 6.8713 5.4028 Mean value 4.82 5.82 6.81 7.80

Standard deviation 0.88 0.88 0.89 0.90 Coefficient of variation 0.18 0.15 0.13 0.11

Exceeding probability of earthquake intensity in the design g p y q y gworking period

KI

ITiIP

exp1)/( （2）

In the formula above, T = 50 years.

2. Distribution function and failure probability ofth k i t it i i diff t i dearthquake intensity in use in different periods

The probability distribution functions of earthquake intensityThe probability distribution functions of earthquake intensity during any t year

KIt

III

ITtIF

exp)(

（3）

For existing structures, any t year means their remaining workinglife. The distribution of earthquake intensity can be decided whenth i i ki lif i ithe remaining working life is given.

The probability of exceeding intensity i in the t year remainingp y g y y gworking life is as follows

KittiIP 1)/(

TtiIP

exp1)/(

（4）

The probability, including the frequent intensity, of exceeding intensity i in the t year remaining working life is

KittiIP

121202.0exp1)/(

（5） 12 （5）

The probability including the basic intensity is

K

IittiIP

121210108.2exp1)/( 3

（6）

nI12 （6）

Small earthquake intensity and design intensity in differentSmall earthquake intensity and design intensity in different remaining working lives can be acquired through the remainingworking life and its corresponding exceeding probability.g p g g p y

In the design working period, the exceeding probability ofg g p g p ystructures which are designed in three design levels is

N

P

111d R

P

11

（7）In the formula R is the recurrent period of a certain design levelIn the formula, R is the recurrent period of a certain design level,N is the design working period.

In the Chinese code for seismic design of buildings, the exceedingprobabilities of small earthquake intensity, middle earthquakeintensity and large earthquake intensity, within 50 years of design working period, are 63.2%, 10% and 2~3% respectively. The corresponding recurrent period are 50 years, 475 years and 1642~2475 years respectively.

Table4 Exceeding probabilities of different design working periodsTable4 Exceeding probabilities of different design working periods

Design working period/a 10 20 30 40 50 60 70 80 90 p

Small earthquake intensity 19.3 33.2 45.5 55.4 63.6 70.2 75.7 80.1 93.8

Middle earthquake intensity 2.1 4.1 6.1 8.1 10 11.9 13.7 15.5 17.3

Large earthquake 0 4~ 0 8~ 1 2~ 1 6~ 2 0~ 2 4~ 2 8~ 3 2~ 3 6~Large earthquake intensity

0.4~0.6

0.8~1.2

1.2~ 18

1.6~2.4

2.0~3.0

2.4~3.6

2.8~4.2

3.2~4.8

3.6~ 5.3

By calculating formulae (6) and (7), using the data in table4, we can get the design intensity for different remaining working periods and the corresponding frequent intensities and rare intensities for a building.

Table5 shows the three-levels intensities in different remaining working periods in Beijing (magnitude 8), calculated according to 50 years design working period.

Table5 Three-levels intensities of different remaining working periods in a magnitude 8 area

Design working period /a 10 20 30 40 50 60 70 80 90

Small earthquake 6 06 6 47 6 69 6 85 6 96 7 05 7 13 7 20 7 26qintensity 6.06 6.47 6.69 6.85 6.96 7.05 7.13 7.20 7.26

Middle earthquake intensity 7.29 7.61 7.79 7.91 8.00 8.07 8.14 8.19 8.23 intensity

Large earthquake intensity 8.02 8.29 8.44 8.54 8.62 8.68 8.73 8.77 8.82

3. Rectification of seismic influence coefficient indifferent working lives The statistical relational formula between peak acceleration AThe statistical relational formula between peak acceleration Aand intensity i is

01.02log10 IA （8）10A （8）The maximum acceleration max of ground motion and the maximum seismic influence coefficient has the followingmaximum seismic influence coefficient max has the following relationship

Amaxmax

gA

（9）

In the Chinese code for the seismic design of buildings =2 25In the Chinese code for the seismic design of buildings, max=2.25, giving the following formula

0102l252 I 01.02logmax 1025.2 I

g （10）

Th i l ti f d ti i 50The maximum acceleration max of ground motion in a 50 year design working period is given in the Chinese code for the seismic design of buildings The rectified coefficient forseismic design of buildings. The rectified coefficient for earthquake action of different design working lives can be acquired from the following formula. the results are shown in acqu ed o t e o ow g o u a. t e esu ts a e s owtable6.

2l

01.02log10 IIIt t

2log

01.02log50max

max 50

5010

1010 II

It

（11）

Table6 Rectified coefficient of earthquake action of different design working lives

Different design working life /a 10 20 30 40 50 60 70 80 90 100

Rectified coefficient 0.37 0.59 0.75 0.88 1.00 1.10 1.20 1.28 1.36 1.43

4 Remaining working life of some extension stadiums4．Remaining working life of some extension stadiums

(1) The Beijing Workers’ Gymnasium. It was built in the early1960’ Th i i ki lif i 25 301960’s. The remaining working life is 25 or 30 years.

(2) The Olympic Stadium Center. It was built in 1998. The remaining working life is 35 years.

The Beijing Workers’ Gymnasium The Olympic Stadium CenterThe Beijing Workers’ Gymnasium The Olympic Stadium Center

IV. The after-utilization of Olympic stadiumsy p At the very beginning of making the development plan for

Beijing Olympic stadiums the principal of centralization andBeijing Olympic stadiums, the principal of centralization and dispersion was paid special attention.

It is divided into 4 regions

One central districtBeijing Olympic Center District

Three areas Three areasThe University Area The West of Beijing AreaThe West of Beijing Area The North Scenic-tourist Area

1. Beijing Olympic Center Districtj g y p

(1) The National Stadium (Bird’s Nest)

It will become a public center for citizens, serving as a sports competition venue conference and exhibition centercompetition venue, conference and exhibition center, entertainment complex and a business and shopping center.

(2) The National Aquatics(2) The National Aquatics Center (Water Cube)

The Water Cube will retain the capability of hosting major p y g jswimming competitions. The future operation projects can be divided into 7 parts, including commercial buildings, a tennis court, a warm-up hall, water paradise

k d t Th ipark and etc. The main project is an artificial surfing beachbeach.

(3) The National ( )Gymnasium

It will be the indoor stadiumIt will be the indoor stadium that possesses the most seats in Beijing and will serve as e j g d w se ve smulti-functional activity center for citizens after the Olympics. The dominant function is to organize national and international professional sports events and large sports and performances with the aim of commerce.

2. The University Area

All the stadiums that are situated on university campuses willAll the stadiums that are situated on university campuses will serve as coaching, training and competition spaces.

The Peking University Gymnasium

The China Agricultural University Gymnasium

The Beijing Science and Technology University G iGymnasium

The Beijing University of Technology Gymnasium

3. The West of Beijing AreaThe Wukesong Culture & Sports Center will fill in the vacancy ofThe Wukesong Culture & Sports Center will fill in the vacancy of large-scale sports facilities in the western area of Beijing.

4. The North Scenic-itourist Area

Th N t l ti it dThe Natural aquatic site and rural racetrack will serve as an attractive zone foran attractive zone for tourists.

R fReferences1. GBJ50011-2001Code for seismic design of buildings [S]. Beijing: China

Architecture & Building Press 2001Architecture & Building Press, 2001.

2. LI Xue-jun, HUO Da. Study on Seismic Fortification Criterion for Existing Gymnasium of 2008 Olympic Games [J] Constuction & Design for ProjectGymnasium of 2008 Olympic Games [J]. Constuction & Design for Project, 2005, No.5, 20-21.

3. MA Yu-hong, XIE Li-li. Seismic design levels of the building with different g, g gimportance factors [J]. Journal of Harbin University of C. E. & Architecture, 2002.10, 35(5), 1-4.

4. WANG Yayong. The introduction of studies on the retrofitting technology of existing sport facilities for Olympic games in Beijing [J]. Sichuan Building S i 2007 12 153 160Science, 2007.12, 153-160.

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