Manuscript title: Use of laminated mechanical joints with metal and - - PowerPoint PPT Presentation

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Manuscript title: Use of laminated mechanical joints with metal and - - PowerPoint PPT Presentation

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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 1 TABLE OF CONTENTS I. About

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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

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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
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  • I. NEWLY PUBLISHED MANUSCRIPT
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Access fees

  • I. NEWLY PUBLISHED MANUSCRIPT
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  • 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

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

(Elliot, 2016)

  • II. OVERVIEW OF CONVENTIONAL CONSTRUCTION PRACTICES
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3) Column-column connections; moment-connection (Elliot, 2016)

  • II. OVERVIEW OF CONVENTIONAL CONSTRUCTION PRACTICES
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5) Beam-column connections; Pin connection (Elliot, 2016)

  • II. OVERVIEW OF CONVENTIONAL CONSTRUCTION PRACTICES

These joints are so weak, and they cannot withstand seismic forces

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6) Beam-column connections; moment connection (Elliot, 2016)

  • II. OVERVIEW OF CONVENTIONAL CONSTRUCTION PRACTICES
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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

  • II. OVERVIEW OF CONVENTIONAL CONSTRUCTION PRACTICES
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Traditional beam-column and column-column joints (Guan et al. 2016) Beam Column Beam Column Drawback(ii): these joints requires temporarily supports to cast the concrete at the joints

Construction point of view:

  • II. OVERVIEW OF CONVENTIONAL CONSTRUCTION PRACTICES

Problems statement for conventional precast frames

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Traditional beam-column and column-column joints (Guan et al. 2016) Drawback(iii): progressive collapse of conventional precast joints

  • II. OVERVIEW OF CONVENTIONAL CONSTRUCTION PRACTICES

Problems statement for conventional precast frames

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

to replace conventional construction practices

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Structural performance

Column-column moment connection

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Test preparations

Column-column moment connection

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Preparation of test specimens

Test preparations

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Preparation of test specimens

Test preparations

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Polishing gauge location

Test preparations

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Loading protocol: cyclic loadings

Column-column moment connection

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Strain measurements and column failure Breaking the test specimens

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Computer model

Numerical computation of the joint

Test set up

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Inputs for nonlinear analysis

Column-column moment connection

Concrete material

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(a) Structural performance

Column-column moment connection Steel-concrete members

Computer simulations using ABAQUS Number of elements: 300,000 Nodes: 340,000 Running time: 5 days

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(a) Structural performance

Column-column moment connection Steel-concrete members

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(a) Structural performance

Column-column moment connection Steel-concrete members

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

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Observations

Column-column moment connection

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Test results

Column-column moment connection

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  • IV. Structural test, erection test and validation of the proposed mechanical joints
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Type A. Erection test IV . Erection test and validation of the proposed mechanical joints

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To be Continued…

Type A. Erection test IV . Erection test and validation of the proposed mechanical joints

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To be Continued…

IV . Erection test and validation of the proposed mechanical joints Type A. Erection test

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To be Continued…

Type A. Erection test IV . Erection test and validation of the proposed mechanical joints

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To be Continued…

Type A. Erection test IV . Erection test and validation of the proposed mechanical joints

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To be Continued…

Type A. Erection test IV . Erection test and validation of the proposed mechanical joints

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To be Continued…

Upper columns Lower columns Bolted metal plates Bolted metal plates Type A. Erection test IV . Erection test and validation of the proposed mechanical joints

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Type B. Connections with one touch couplers Erection test IV . Erection test and validation of the proposed mechanical joints

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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 1100 mm Erection test Type B. Connections with one touch couplers IV . Erection test and validation of the proposed mechanical joints

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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 Type B. Connections with one touch couplers IV . Erection test and validation of the proposed mechanical joints

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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 Type B. Connections with one touch couplers IV . Erection test and validation of the proposed mechanical joints

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Lifting concrete beams

IV . Erection test and validation of the proposed mechanical joints

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Upper column Upper column Lower column Lower column Bolt Lower Plate Upper Plate Lower Plate Upper Plate One touch coupler Type B. Connections with one touch couplers IV . Erection test and validation of the proposed mechanical joints

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

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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

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Test preparation

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  • 800
  • 600
  • 400
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200 400 600

  • 150
  • 100
  • 50

50 100 150

Load (kN) 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 to the bolts failure (bolts fractured) Peak (-80 mm, -606 kN) Peak (106 mm, 520 kN)

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Push Pull

Moment at the joint level (680 kN-m) Push Pull

Test results

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(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

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Failure modes for specimen C1

(b) Failure modes at the stroke of 108 mm

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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

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Failure modes for specimen C1

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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

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Failure modes for specimen C1 (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

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Test results

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Disassemble of mechanical joint after the test Upper column unit Upper plate Nut connecting upper column rebars

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Test results

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  • 1000
  • 800
  • 600
  • 400
  • 200

200 400 600 800 1000

  • 250
  • 200
  • 150
  • 100
  • 50

50 100 150 200 250

Load (kN) Displacement (mm)

Specimen C2: Load - displacement curve

Fracture of two interior bolts at 91 mm of stroke Load dropped due to the bolts failure Peak (-130 mm, -846 kN) Peak (89.5 mm, 699 kN) * A total of 6 bolts fractured during the test

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Push Pull

Moment at the joint level (1,360 kN-m) Push Pull

Test results

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Failure modes for specimen C2

(a) Failure modes at the stroke of 81 mm Lateral displacement (81 mm) Deflected shape Concrete cracks initiated

Test results

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(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

Failure modes for specimen C2

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Test results

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(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

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Failure modes for specimen C2

(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

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Test results

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  • 1200
  • 1000
  • 800
  • 600
  • 400
  • 200

200 400 600 800 1000

  • 200
  • 150
  • 100
  • 50

50 100 150 200

Load (kN) Displacement (mm)

Specimen C3: Load - displacement curve

Peak (-107 mm, -938 kN) Peak (102 mm, 800 kN)

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Push Pull

Moment at the joint level (1,360 kN-m) Push Pull

Test results

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Failure modes for specimen C3

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

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Test results

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200 400 600 800 1000

  • 250
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  • 100
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50 100 150 200 250

Load (kN) Displacement (mm)

Load - displacement curve

  • 1. Push : Specimen C1
  • 2. Push : Specimen C2
  • 3. Push : Specimen C3
  • 4. Pull : Specimen C1
  • 5. Pull : Specimen C2
  • 6. Pull : Specimen C3

(-98,-777) (-33,-428)

Concrete strain = 0.003

(Concrete strain for C3: did not reach 0.003, gauge malfunction) (100,600) (77,500)

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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

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Erection test

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Erection test

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Erection test

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Erection test

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Erection test

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Erection test

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Erection test

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NUMERICAL INVESTIGATION; STRUCTURAL PERFORMANCE

Nonlinear finite element analysis

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Linear Analysis; Pushover analysis

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(b) FE model (a) Test set up

Loading Nonlinear analysis based on ABAQUS

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FE modeling techniques Meshing

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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

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FE modeling techniques Meshing

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FE modeling techniques Meshing

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  • FE modeling techniques

Contacts: Column-column

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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

FE modeling techniques Contacts

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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

FE modeling techniques Contacts

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FE results

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  • VI. MODULAR CONSTRUCTION IN PRECAST CONCRETE INDUSTRY

Ongoing research

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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

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Modular construction; Cellular-type buildings

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Modular construction; Cellular-type buildings

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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

  • f 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

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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)

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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.
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(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.

Modular construction, Construction sequence

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(4) (i) (ii) Modular construction, Completed structure

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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.

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Thank you for your attention