1、 Introduction of precast structure over the world

2、Structure analysis of wall-slab system of Broad

3、 Lab test of connections and analysis

4、Calculation and modeling

5、Company technical specification

6、Finished projects

Content

1、 Introduction of precast structure

over the world

Precast building project in Finland

Precast technic in Japan

Precast Residential Park

Precast Buildings' Behaviors

in the Big Earthquake in Osaka and Kobe

• Jan 17th,1995

• Magnitude : 7.2

• Last 20 second

• Cost : over 100 billion Dollar

• Casualty : 6434 death

WPC Building Survived in this Earthquake

2. Structure analysis of wall-slab system of Broad

Basic theory of box system:

1. Divided the out coming force from any direction

into 3 orthogonal force

2. One pair only response to the force that parallel

to the wall plane

3. The walls react as uniform monolithic block to

the shear force

4. Several boxes work together to form

globe structure with multiple safety protection

Connection between walls

Connection between walls

Connection between wall and slab

The steel loop embedded in PC

Gap finishing between precast plate

Foam stick

Silicone weatherproof sealant

Advantages of the sealant

Maintainability Easy surface

finishing Convenient

construction

EconomicalShoot fiber forming Paintable Weatherproof

3. Lab test of connections and analysis

Test of the connection

The test of foundation-wall connection

The test of adjacent walls connection

The test of adjacent slabs connection

The test of foundation-wall connection

Test element----G1

Test element----G2

The test of foundation-wall connection

The test of foundation-wall connection

The test of foundation-wall connection

The test of foundation-wall connection

Wreck on the PC wall

The test of foundation-wall connection

Cracks on the foundation

Result analysis

0 10 20 30 40 50 60 70 800

50

100

150

200

250

300

350

荷载

/kN

位移 /mm

JD1 (2 dowel bar)

0 10 20 30 40 50 60 70 800

50

100

150

200

250

300

350

荷载

/kN

位移 /mm

JD2 (2 dowel bar)

The test of adjacent walls connection

Cross-section of wall connection

Three sets of test(2 with Ф16 rebar, 1 with Ф12 rebar )

The test of adjacent walls connection

Test sample

Test process

Displacement and fail

0 5 10 15 20 25 300

100

200

300

400

500

600

荷载 /kN

位移 /mm

0 5 10 15 20 25 300

100

200

300

400

500

600

荷载 /kN

位移 /mm

JD7（3 pair 6 steel wire） JD8 （3 pair 6 steel wire）

Results analysis

Results analysis

0 5 10 15 20 25 300

100

200

300

400

500

600

荷载 /kN

位移 /mm

JD9（3 pair 6 steel wire）

The test of adjacent slabs connection

The test of adjacent slabs connection

The test of adjacent slabs connection

Summary of the tests of connections

4、Calculation and modeling

Other component check4.4

Detail design requirement4.2

Result and analysis4.3

General requirement of structure4.1

Based on probability theory and limit state design method , and adjustment coefficient to design the structure components

Ultimate limit states and serviceability limit states are considered in designing

The duration of serviceability of precast structure and components should extend the designed duration without major repair

Using precast load bearing wall, and single block precast slab to form a box system, with the dowel bar and steel loop to connect

The whole structure is composited with vast box systems, which bring redundant safe factor to the building

Design principle

General requirement of structure4.1

《Code for seismic design of buildings》GB50011-2010

《Code for design of masonry structure》GB50003-2011

《 Code for design and construction of assembling buildings》JGJ1-91

《Unified standard for reliability design of building structures》GB50068-2001

《Load code for the design of building structures》GB50009-2012

《Code for design of concrete structure》GB50010-2010

《Steel wire rope for important purpose》GB8918-2006

Regulations

Concrete

Rebar

Steel wire loop

C35HRB400

Tension strength

1770MPa

Material

Bearing capacity of ultimate limit state

Safety factor γ0----- 1.0 for residential building, required duration 50 years

SGk ---- standard value of dead load；

SQ1k ---- standard value of live load;

SQik----standard value of governed variable load；

R(·)----function of structure resistance；

f ---- design value of masonry ，f＝fk/γf；

fk ---- standard value of masonry ，

γf ---- material coefficient of masonry structure ，usually γf＝1.6

SG1K---- normal value of positive effect dead load

SG2K---- normal value of negative effect dead load

Overturning, sliding and floating check

House Category

Minimum wall

thickness（mm）

Design value of acceleration of earthquake

6 Degree 7 Degree

0.05g 0.10g 0.15g

height story height story height story

Multi-story Assembled precast wall-slab structure

180 30 9 30 9 30 9

150 30 9 30 9 26 8

Multi-story Assembled precast wall-slab structure

with bottom frame and shear wall

180 30 9 30 9 26 8

150 30 9 30 9 26 8

Limit of height and stories（m）

Table 4.1

Categories of floor system

Stiffness analysis

scheme

Semi-elastic analysis scheme

elasticanalysisscheme

1 Monolithic and assembled monolithic concrete plate floor

s＜32 32≤s≤72 s＞72

2Assembled precast girder

transfer floor, light steel floor and wood girder floor

s＜20 20≤s≤48 s＞48

3Wood floor with tile and light

steel floors＜16 16≤s≤36 s＞36

In table, s indicates span between cross walls, The unit is meter

Elastic analysis scheme is processed in case of no cross wall

Stiffness analysis scheme

Table 4.2

1

3

2

Requirement of cross wall

The area of the opening must not extend the

50% of the area of the cross wall

The thickness of the cross wall should more than

180 mm

The length of the cross wall should longer than height

of the story for single story building, and should

longer than the height of length for multi-story building

Multi-story building:

Under vertical load : wall and column are considered as pin connection

in both ends within one span

Under horizontal load : wall and column are considered as vertical

continuous cantilever beam

Single-story house：roof wall connection = pin connection

foundation wall connection = fixed connection

Assumption of stiffness analysis scheme

The area of the hole of exterior wall is less

than 2/3 of exterior wall

The height of the building is within the limit

of table 4.2

Dead load of the roof slab > 0.8kN/m2

Wind load analysis

“Code for design of masonry structure” says that wind load affect can be

neglected if the 3 conditions can be satisfied simultaneously in analysis of

structure

Wind velocity pressure

(kN/m2)

Height of story(m)

Total height

(m)

0.4 4.0 28

0.5 4.0 24

0.6 4.0 18

0.7 3.5 18

Height limit to neglect the wind load

Table 4.3

Detail design requirement4.2

Categories of floor system range

Monolithic and assembled monolithic

concrete system

With isolation 50m

Without isolation 40m

Assembled precast plate floor system

With isolation 60m

Without isolation 50m

Assembled precast girder transfer floor

system

With isolation 75m

Without isolation 60m

Wood floor with tile and light steel floor 100m

Maximum range interval of expansion and contraction joint

Table 4.4

Maximum range interval of cross wall

Category of structure

Seismicintensity

6 7

Assembled precast multi-story

building

Monolithic and assembled monolithic concrete system

15m 15m

Assembled precast plate floor system 11m 11m

Assembled precast multi-story

building with bottom frame

Assembled part

Same as assembled precast multi-story

building

Bottom frame structure

(less than 2 stories) 18m 15m

Table 4.5

---- nominal height of wall or column

---- thickness of wall or relative length of rectangle column

---- modified coefficient for load bearing wall = 1.2, when h=240mm; = 1.5 when, h = 90mm

: use interpolation method when 90mm < h < 240mm

---- modified coefficient for opening

bs = the width of the opening

s = distance between axial line of walls at the two side of the opening

---- limited value of ratio of height to sectional thickness

(usual value = 30, for precast wall)

OH

h1

2

Ratio of height to sectional thickness of wall or column

1

S

bs4.012

1

1

Ratio of height to sectional thickness is determined by

Result and analysis4.3

Compression

resistance

check of wall

Ratio of height

to sectional

thickness

checkof wall

Ultimate

limit state

vertical

connection

strength check

of wall

Horizontal

connection

strength check

of walls

Modeling of multi-story building

Use the structural analysis

software PKPM, which

issued by China Academy

of Building Research

Ratio of the resistance and the effect of earthquake：

Ratio of height to sectional thickness of wall

Other component check4.4

• Steel loop strength check

to define the material, the size, the quantity

and the space between each other

• Lifting bolt strength check

to define the tensile strength, the in-concrete length,

to well arrange the location of the bolts

• Dowel bar strength check

shear strength check

Based on the theoretical research and laboratory test of the assembled precast multi-story building , Broad compiled the enterprise specification “Technical specification for assemble precast wall-slab structure multi-story building”

And the specification is accredited by structural expert jury.。

5. Company technical specification

6. Finished projects