Manuscript title: Use of laminated mechanical joints with metal … · 2018-07-03 · 2 TABLE OF...

1

Manuscript title:

Use of laminated mechanical joints with metal and concrete

plates for precast concrete columns

Prepared by :

Dr. JD NZABONIMPA (PhD in Structural Engineering)

INES-Ruhengeri University, Rwanda

2

TABLE OF CONTENTS

I. About the newly published manuscript

II. Overview of the conventional construction practices

-Problem statement

III. Proposed mechanical joints for the automation of precast concrete frames

-Necessity of our study and motivation of our research.

IV. Structural test, erection test, and validation of the proposed mechanical joints

V. Ongoing research: Modular construction in precast concrete industry

VI. Conclusion

3

I. NEWLY PUBLISHED MANUSCRIPT

4

Access fees I. NEWLY PUBLISHED MANUSCRIPT

5

II. OVERVIEW OF CONVENTIONAL CONSTRUCTION PRACTICES

1) Column base plate connections; moment connection

(Precast concrete institute) (Elliot, 2016)

Reference: https://www.pci.org/Connections

Precast column

Base plate Anchor bolt

6

2) Column-to-foundation connection using grouted pocket; moment connection

(Elliot, 2016)


7

3) Column-column connections; moment-connection

(Elliot, 2016)


8

5) Beam-column connections; Pin connection

(Elliot, 2016)


These joints are so weak,

and they cannot withstand

seismic forces

9

6) Beam-column connections; moment connection

(Elliot, 2016)


10

Problems statement for conventional precast frames

Construction point of view:

Traditional beam-column and column-column joints (Guan et al. 2016)

Drawback (ii): These joints

requires temporarily supports to

cast the concrete at the joints

Drawback (3): The construction

period is lengthened

Drawback (i): Concrete

pour forms are required

to cast the concrete Beam

Beam

Column

Column


11


Beam

Column

Beam

Column

Drawback(ii): these joints requires temporarily

supports to cast the concrete at the joints

Construction point of view:



12


Drawback(iii): progressive collapse of conventional

precast joints



13

III. Proposed mechanical joint connections (Lego-type connections)

to replace conventional construction practices

14

Structural performance

Column-column moment connection

15

Test preparations


16

Preparation of test specimens

Test preparations

17

Preparation of test specimens

Test preparations

18

Polishing gauge location Test preparations

19

Loading protocol: cyclic loadings


20

Strain measurements and column failure

Breaking the test specimens

21

Computer model

Numerical computation of the joint

Test set up

22

Inputs for nonlinear analysis


Concrete material

23

(a) Structural performance


Steel-concrete members

Computer simulations using ABAQUS

Number of elements: 300,000

Nodes: 340,000

Running time: 5 days

24




25




ABAQUS vs Test; Specimen C1 (20 mm thick column plates)

26

Observations


27

Test results


28

IV. Structural test, erection test and validation of the proposed mechanical joints

29

Type A. Erection test

IV. Erection test and validation of the proposed mechanical joints

30

To be Continued…



31

To be Continued…



32

To be Continued…



33

To be Continued…



34

To be Continued…



35

To be Continued…

Upper columns

Lower columns

Bolted metal plates Bolted metal plates



36

Type B. Connections with one touch couplers

Erection test


37

Upper column

Size: 1200 x 1200 mm

Lower column

Size: 1200 x 1200 mm

Girder

Size: 1100 x 800 mm

One touch coupler (D32) Coupler for connecting

girder re-bars (D29) Upper plate

Size: 1400 x 1400 x 10 mm

Lower plate

(1400 x 1400 x 10 mm) Bolts (M20)

Extended end plate

Size: 995 x 800 mm

Slab

(250 mm)

Girder Welding coupler

11

00

mm

Erection test



38

Crane Upper column unit Upper column unit

One toucher coupler

(female part) Rebar (male part)

Rebar inserted into one

touch coupler

Sequence

1 2

3 4

Erection test



39

Upper

column unit

Lower column unit

Upper plate

Lower plate

Upper

column unit

Lower

column unit

One touch

coupler Upper plate

Lower plate Bolt

5 6

Sequence

Erection test



40

Lifting concrete beams


41

Upper

column Upper

column

Lower

column

Lower

column

Bolt

Lower

Plate

Upper

Plate

Lower Plate

Upper Plate

One touch coupler



42

IV. Structural Test [IRREGULAR L-TYPE LEGO FRAMES]

43

Geometric configuration of test specimens

In this study, L-type column sections are introduced with the aim of replacing rectangular columns that

do not fit at the corners. These columns are preferred by architects due to their architectural flexibility

at the corners of the walls in residential buildings.

Joint level

1 m

1.7 m

Foundation

(Size: 2.5m x 2.5m x 0.5m)

Foundation support

(constrained area)

Foundation support

(constrained area)

Actuator (cyclic loads)

0.3 m

3.0 m

Push

Pull

Typical test specimen layout

44

Test preparation

-800

-600

-400

-200

0

200

400

600

-150 -100 -50 0 50 100 150

Load

(k

N)

Displacement (mm)

Specimen C1: Load - displacement curve

Fracture of 2 bolts at

108 mm of stroke

Load dropped due

to the bolts failure

(bolts fractured)

Fracture of 2 bolts at

108 mm of stroke

* A total of 9 bolts

fractured during

the test

Load dropped due


(bolts fractured)

Peak (-80 mm, -606 kN)

Peak (106 mm, 520 kN)

45

Push

Pull

Moment at the joint

level (680 kN-m)

Push

Pull

Test results

46

(a) Failure modes at the stroke of 54 mm

Lateral

displacement

(54 mm)

Deflected shape Concrete started crushing due to

compression

Concrete cracks initiated Failure modes for specimen C1

Test results

Failure modes for specimen C1

(b) Failure modes at the stroke of 108 mm

47

At a stroke 81 mm, small separation

between metal plates was observed At a stroke 108 mm, first bolt fractured

Upper column

Lower column

Upper plate Filler plate

Lower plate

Separation between metal plates starts

increasing at a stroke of 108 mm

Test results


48

At stroke 135 mm, 9 bolts fractured; the end of the test

Bolts fractured

Concrete crushed due to compression

(c) Failure modes at the end of the test

Test results


(d) Metal plates deformation measured at the end of the test

Upper plate Lower plate

Plate deformation: 2 mm Plate deformation: 3 mm

Nuts connecting rebars from

lower column

Nuts connecting rebars from

upper column

49

Test results

Disassemble of mechanical joint after the test

Upper column unit

Upper plate

Nut connecting upper

column rebars

50

Test results

-1000

-800

-600

-400

-200

0

200

400

600

800

1000

-250 -200 -150 -100 -50 0 50 100 150 200 250

Lo

ad

(k

N)

Displacement (mm)

Specimen C2: Load - displacement curve Fracture of two interior

bolts at 91 mm of stroke

Load dropped due


Peak (-130 mm, -846 kN)

Peak (89.5 mm, 699 kN)

* A total of 6 bolts

fractured during

the test

51

Push

Pull

Moment at the joint

level (1,360 kN-m)

Push

Pull

Test results

52


(a) Failure modes at the stroke of 81 mm

Lateral

displacement

(81 mm)

Deflected shape Concrete cracks initiated

Test results

(b) Failure modes at the stroke of 165 mm

Bolts fracture Separation of metal plates Bolts failure

Upper plate

Filler plate Lower plate

Upper column

Lower column


53

Test results

54

(c) Failure modes and deflected shapes at the stroke of 183 mm

Concrete crushed due

to compression

Separation of metal plates

Concrete crushed due

to compression

Upper column

Lower column

Lower column

Upper column

Load Load Test results


(d) Failure modes at the end of the test

Upper plate

Bolts fracture

Upper column

Lower column

Upper column

Lower column

Concrete crushed due to

compression Concrete crushed due to

compression

Separation of metal plates

Separation of metal

plates

Filler plate

Lower plate

55

Test results

-1200

-1000

-800

-600

-400

-200

0

200

400

600

800

1000

-200 -150 -100 -50 0 50 100 150 200

Load

(k

N)

Displacement (mm)

Specimen C3: Load - displacement curve

Peak (-107 mm, -938 kN)

Peak

(102 mm, 800 kN)

56

Push

Pull

Moment at the joint

level (1,360 kN-m)

Push

Pull

Test results


Failure modes at the stroke of 162 mm; end of the test

Concrete crushed

due to compression

Rebar and L-shaped

steel bent due to

compressive force

57

Test results

-1200

-1000

-800

-600

-400

-200

0

200

400

600

800

1000

-250 -200 -150 -100 -50 0 50 100 150 200 250

Load

(k

N)

Displacement (mm)

Load - displacement curve

1. Push : Specimen C1



4. Pull : Specimen C1



(-98,-777)

(-33,-428)

Concrete strain = 0.003 (Concrete strain for C3: did not reach

0.003, gauge malfunction)

(100,600)

(77,500)

58

Point A

Point D

Point E Push

Pull Point C

Moment at the joint

level (1,360 kN-m)

Point B

Point F

Design moment (Mu= 350 kN-m)

Test results

59

Erection test

60

Erection test

61

Erection test

62

Erection test

63

Erection test

64

Erection test

65

Erection test

66

NUMERICAL INVESTIGATION; STRUCTURAL PERFORMANCE

Nonlinear finite element analysis

67

Linear Analysis; Pushover analysis

68

(b) FE model (a) Test set up

Loading

Nonlinear analysis based on ABAQUS

FE modeling techniques

Meshing

69

Column

Loading

Joint

Foundation

500

3000

1960

Typical specimen

for L-type columns

(LC1-WF)

Control specimen

for L-type columns

(LC3-WF)

[ Elements: 735,000 ] [ Elements: 453,000 ] [Unit: mm]

3000

Loading


Meshing

70


Meshing

71


Contacts: Column-column

72

Plate: master

Concrete: slave

Interior bolts: master

Plate: slave

Exterior bolts: master

Plate: slave

Upper plate: master

Lower plate: slave

Re-bar and nut: master

Plate: slave

Upper nut: master

Lower nut: slave


Contacts

73

Plate: master

Concrete: slave

Interior bolts: master

Plate: slave

Exterior bolts: master

Plate: slave

Upper plate: master

Lower plate: slave

Re-bar and nut: master

Plate: slave

Upper nut: master

Lower nut: slave


Contacts

74

75

FE results

76

VI. MODULAR CONSTRUCTION IN PRECAST CONCRETE INDUSTRY

Ongoing research

77

Modular construction; Cellular-type buildings

It was demonstrated that building off-site offers many

advantages including better construction management,

improvement of safety and security, and substantial

reduction in the construction period.

Disadvantages of conventional modular structures

1. Limitation in their applications;

They are not suitable for high-rise buildings

2.Inadequate structural joints to resist seismic loads

Advantages of conventional modular structures

78


79


80

Modular construction for high-rise buildings

25-story modular building in Wolverhampton,

England, during construction (image by R. M. Lawson)

Originally, these models are designed to resist only gravity loads.

However, in order to have a building of 25 storeys, the stability

of the building under wind must be checked. Engineers uses

either steel core or concrete core to take of lateral forces. In

some applications, braces within the walls of modules were used.

However, these steel frames and braces are so expensive,

making the modular construction unattractive for contractors.

1. Corner-supported modules, in which loads are

transferred via edge beams to corner posts

2. Load-bearing modules, in which loads are

transferred through the side walls of the modules

81

Modular construction for high-rise buildings

2. Corner-supported modules, in which loads are

transferred via edge beams to corner posts

-Square hollow sections are often used due to their

high buckling resistance

1. Load-bearing modules, in which loads are

transferred through the side walls of the modules

-Light steels C sections are used with concrete

walls to resist compressive forces

Light steel module with a perimeter framework (image by R. M. Lawson)

82

Modular construction,

Construction sequence

One module

(1)

(2)

One module

1. No limitation in the applications of these modular frames;

The proposed modular construction can be applied to high-rise buildings

2. Adequate structural joints to resist seismic loads are guaranteed.

83

(3)

1. No limitation in the applications of these modular frames;

The proposed modular construction can be applied to high-rise buildings

2. Adequate structural joints to resist seismic loads are guaranteed.


Construction sequence

84

(4)

(i)

(ii)


Completed structure

85

VI: Conclusion

1. Contribution to the effortless erection of moment frames, and to their rapid

assembly, similar to that accomplished using steel frames.

2. Plates with thin plates were not recommended to be used for moment

frames due to their severe deformations during the test.

3. Introduction of computer simulations replaced a large number of experiments

4. The proposed precast structures can be used as human shelters in case of

disasters such as earthquakes and so on. This is because a complete structure

can be available within a short time.

86

Thank you for your attention

Manuscript title: Use of laminated mechanical joints with metal … · 2018-07-03 · 2 TABLE OF...

Documents

Transcript of Manuscript title: Use of laminated mechanical joints with metal … · 2018-07-03 · 2 TABLE OF...