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 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 2
I. NEWLY PUBLISHED MANUSCRIPT 3
Access fees I. NEWLY PUBLISHED MANUSCRIPT 4
II. OVERVIEW OF CONVENTIONAL CONSTRUCTION PRACTICES 1) Column base plate connections; moment connection Precast column Base plate Anchor bolt (Precast concrete institute) (Elliot, 2016) Reference: https://www.pci.org/Connections 5
II. OVERVIEW OF CONVENTIONAL CONSTRUCTION PRACTICES 2) Column-to-foundation connection using grouted pocket; moment connection (Elliot, 2016) 6
II. OVERVIEW OF CONVENTIONAL CONSTRUCTION PRACTICES 3) Column-column connections; moment-connection (Elliot, 2016) 7
II. OVERVIEW OF CONVENTIONAL CONSTRUCTION PRACTICES 5) Beam-column connections; Pin connection These joints are so weak, and they cannot withstand seismic forces (Elliot, 2016) 8
II. OVERVIEW OF CONVENTIONAL CONSTRUCTION PRACTICES 6) Beam-column connections; moment connection (Elliot, 2016) 9
II. OVERVIEW OF CONVENTIONAL CONSTRUCTION PRACTICES Problems statement for conventional precast frames Column Construction point of view: Drawback (i): Concrete pour forms are required to cast the concrete Beam Drawback (ii): These joints requires temporarily supports to cast the concrete at the joints Beam Drawback (3): The construction Column period is lengthened Traditional beam-column and column-column joints (Guan et al. 2016) 10
II. OVERVIEW OF CONVENTIONAL CONSTRUCTION PRACTICES Problems statement for conventional precast frames Construction point of view: Drawback(ii): these joints requires temporarily supports to cast the concrete at the joints Column Beam Beam Column Traditional beam-column and column-column joints (Guan et al. 2016) 11
II. OVERVIEW OF CONVENTIONAL CONSTRUCTION PRACTICES Problems statement for conventional precast frames Drawback(iii): progressive collapse of conventional precast joints Traditional beam-column and column-column joints (Guan et al. 2016) 12
III. Proposed mechanical joint connections (Lego-type connections) to replace conventional construction practices 13
Column-column moment connection Structural performance 14
Column-column moment connection Test preparations 15
Preparation of test specimens Test preparations 16
Preparation of test specimens Test preparations 17
Polishing gauge location Test preparations 18
Column-column moment connection Loading protocol: cyclic loadings 19
Breaking the test specimens Strain measurements and column failure 20
Numerical computation of the joint Computer model Test set up 21
Column-column moment connection Concrete material Inputs for nonlinear analysis 22
Column-column moment connection Steel-concrete members (a) Structural performance Computer simulations using ABAQUS Number of elements: 300,000 Nodes: 340,000 Running time: 5 days 23
Column-column moment connection Steel-concrete members (a) Structural performance 24
Column-column moment connection Steel-concrete members (a) Structural performance ABAQUS vs Test; Specimen C1 (20 mm thick column plates) 25
Column-column moment connection Observations 26
Column-column moment connection Test results 27
IV. Structural test, erection test and validation of the proposed mechanical joints 28
IV . Erection test and validation of the proposed mechanical joints Type A. Erection test 29
IV . Erection test and validation of the proposed mechanical joints Type A. Erection test To be Continued… 30
IV . Erection test and validation of the proposed mechanical joints Type A. Erection test To be Continued… 31
IV . Erection test and validation of the proposed mechanical joints Type A. Erection test To be Continued… 32
IV . Erection test and validation of the proposed mechanical joints Type A. Erection test To be Continued… 33
IV . Erection test and validation of the proposed mechanical joints Type A. Erection test To be Continued… 34
IV . Erection test and validation of the proposed mechanical joints Type A. Erection test Upper columns Bolted metal plates Bolted metal plates Lower columns To be Continued… 35
IV . Erection test and validation of the proposed mechanical joints Type B. Connections with one touch couplers Erection test 36
IV . Erection test and validation of the proposed mechanical joints Upper column Type B. Connections with one touch couplers Size: 1200 x 1200 mm One touch coupler (D32) Coupler for connecting Upper plate girder re-bars (D29) Size: 1400 x 1400 x 10 mm Slab 1100 mm (250 mm) Erection test Girder Welding coupler Lower plate Bolts (M20) (1400 x 1400 x 10 mm) Extended end plate Girder Size: 995 x 800 mm Size: 1100 x 800 mm Lower column Size: 1200 x 1200 mm 37
IV . Erection test and validation of the proposed mechanical joints Type B. Connections with one touch couplers Crane Upper column unit Upper column unit Erection test Sequence 1 2 3 4 Rebar inserted into one One toucher coupler Rebar (male part) touch coupler (female part) 38
IV . Erection test and validation of the proposed mechanical joints Type B. Connections with one touch couplers One touch Upper Upper column unit coupler column unit Upper plate Upper plate Erection test Sequence 5 6 Lower plate Lower Lower plate Bolt Lower column unit column unit 39
IV . Erection test and validation of the proposed mechanical joints Lifting concrete beams 40
IV . Erection test and validation of the proposed mechanical joints Type B. Connections with one touch couplers Upper Upper column column Lower Lower column column Upper Plate Upper Plate Lower Lower Plate Plate One touch coupler Bolt 41
IV. Structural Test [IRREGULAR L-TYPE LEGO FRAMES] 42
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. 43
Test preparation Actuator (cyclic loads) Typical test specimen layout 0.3 m Push Pull 1.7 m 3.0 m Joint level 1 m Foundation support Foundation Foundation support (constrained area) (Size: 2.5m x 2.5m x 0.5m) (constrained area) 44
Test results Peak (106 mm, 520 kN) Fracture of 2 bolts at 108 mm of stroke Specimen C1: Load - displacement curve 600 Push Moment at the joint Load dropped due 400 to the bolts failure level (680 kN-m) (bolts fractured) Load dropped due 200 to the bolts failure Load (kN) (bolts fractured) 0 * A total of 9 bolts -200 fractured during the test -400 Pull -600 Peak (-80 mm, -606 kN) -800 Push -150 -100 -50 0 50 100 150 Pull Displacement (mm) Fracture of 2 bolts at 108 mm of stroke 45
Failure modes for specimen C1 Test results Concrete cracks initiated Lateral displacement (54 mm) Concrete started crushing due to Deflected shape compression (a) Failure modes at the stroke of 54 mm 46
Test results Failure modes for specimen C1 Separation between metal plates starts Filler plate increasing at a stroke of 108 mm Upper plate Upper column Lower column At a stroke 81 mm, small separation At a stroke 108 mm, first bolt fractured Lower plate between metal plates was observed (b) Failure modes at the stroke of 108 mm 47
Test results Failure modes for specimen C1 Bolts fractured Concrete crushed due to compression At stroke 135 mm, 9 bolts fractured; the end of the test (c) Failure modes at the end of the test 48
Test results Failure modes for specimen C1 Nuts connecting rebars from Nuts connecting rebars from lower column Lower plate upper column Upper plate Plate deformation: 2 mm Plate deformation: 3 mm (d) Metal plates deformation measured at the end of the test 49
Test results Upper plate Nut connecting upper column rebars Upper column unit Disassemble of mechanical joint after the test 50
Test results Fracture of two interior Specimen C2: Load - displacement curve bolts at 91 mm of stroke 1000 Moment at the joint Push Load dropped due * A total of 6 bolts 800 level (1,360 kN-m) to the bolts failure fractured during 600 the test Peak (89.5 mm, 699 kN) Load (kN) 400 200 0 -200 -400 -600 Pull -800 Push -1000 -250 -200 -150 -100 -50 0 50 100 150 200 250 Pull Displacement (mm) Peak (-130 mm, -846 kN) 51
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