Designing moment resisting connection for disassembly for implementation in precast reinforced concrete buildings

DESIGNING MOMENT-RESISTING CONNECTION FOR DISASSEMBLY FOR IMPLEMENTATION IN PRECAST REINFORCED CONCRETE BUILDINGS LIN ZHISHENG NATIONAL UNIVERSITY OF SINGAPORE 2013 DESIGNING MOMENT-RESISTING CONNECTION FOR DISASSEMBLY FOR IMPLEMENTATION IN PRECAST REINFORCED CONCRETE BUILDINGS LIN ZHISHENG (M.Eng, SCUT) A THESIS SUBMITTED FOR THE DEGREE OF DOCTOR OF ENGINEERING DEPARTMENT OF CIVIL AND ENVIRONMENTAL ENGINEERING NATIONAL UNIVERSITY OF SINGAPORE 2013 Designing Moment-Resisting Connection for Disassembly for Implementation in Precast Reinforced Concrete Structure Declaration Page I hereby declare that this thesis is my original work and it has been written by me in its entirety. I have duly acknowledged all the sources of information which have been used in the thesis. This thesis has also not been submitted for any degree in any university previously. LIN ZHISHENG 30 July 2013 Designing Moment-Resisting Connection for Disassembly for Implementation in Precast Reinforced Concrete Structure ACKNOWLEDGEMENT The author would like to make use of this opportunity to acknowledge various individuals for their guidance and encouragement in the course of this research. Firstly, the author would like to express his appreciation for the constant guidance, valuable advice, constructive suggestions and encouragement provided by his supervisor, Associate Professor Gary Ong Khim Chye. Secondly, the author would like to extend his deep appreciation to Dr. Lado Riannevo Chandra and Dr. Patria Kusumaningrum for their helpful advice on this research. The author is also grateful for the assistance provided by the staff in the NUS Structural Engineering Lab. Special appreciation to the National University of Singapore for the generously granting the research scholarship and excellent academic environment for the period of research. This research project was funded by Ministry of National Development (MND) of Singapore. This research was made possible due to funding from the research project, Design for Disassembly (DfD) Building Systems for Singapore. The author profoundly acknowledges his parents, wife and friends for their constant encouragement and invaluable support for motivating him to pursue and complete this research work. i Designing Moment-Resisting Connection for Disassembly for Implementation in Precast Reinforced Concrete Structure TABLE OF CONTENTS ACKNOWLEDGEMENT . i TABLE OF CONTENTS ii SUMMARY . ix NOTATIONS . xi LIST OF TABLES . xiv LIST OF FIGURES xv CHAPTER INTRODUCTION AND LITERATURE REVIEW 1.1 Introduction . 1.1.1 Background 1.1.2 Design for Disassembly (DfD) 1.1.3 Precast concrete technology . 1.1.4 Precast connections between beams and columns . 1.2 Literature review . 1.2.1 Demountable precast building systems in practice 1.2.2 Principles of DfD . 12 1.2.3 Conventional precast beam-column connection 16 1.2.4 Current practice in HDB apartment blocks 19 1.2.5 DDC system and mechanical rebar splicing techniques 21 1.2.6 Bolted endplate connections in steel construction . 24 ii Designing Moment-Resisting Connection for Disassembly for Implementation in Precast Reinforced Concrete Structure 1.2.7 Location of precast connection between beams and columns . 26 1.2.8 Demolition methods for removing small volume of concrete . 28 1.3 Objectives and scopes . 30 1.4 Organization of the thesis . 32 CHAPTER CONCEPTUAL DESIGN AND PRELIMINARY NUMERICAL ANALYSIS OF THE PROPOSED DFD M-R CONNECTION . 36 2.1 Conceptual design proposal 36 2.1.1 Introduction 36 2.1.2 Reuse flexibility consideration with respect to span of beam 37 2.1.3 Three alternative designs . 42 2.2 Structural properties of the proposed DfD connection . 44 2.2.1 Moment capacity 45 2.2.2 Shear force capacity . 48 2.2.3 Rotational stiffness . 48 2.3 Preliminary numerical analysis of the proposed DfD M-R connection 49 2.3.1 Detail of the specimens for preliminary numerical analysis 50 2.3.2 Finite element modelling . 51 2.3.2.1 General modeling description . 51 2.3.2.2 Concrete model . 53 2.3.2.3 Boundary conditions . 57 2.3.3 Result and discussion . 58 2.3.3.1 Moment vs. mid-span deflection . 58 iii Designing Moment-Resisting Connection for Disassembly for Implementation in Precast Reinforced Concrete Structure 2.3.3.2 Stress distribution in the embedded steel elements . 59 2.3.3.3 Crack propagation . 61 2.4 Conclusions . 64 CHAPTER EXPERIMENTAL INVESTIGATION OF THE PROPOSED DFD M-R CONNECTION 66 3.1 Introduction . 66 3.2 Phase-1—four-point-bending test . 67 3.2.1 Specimens and test setup . 67 3.2.2 Results and discussion . 74 3.2.2.1 Moment resistance 74 3.2.2.2 Ductility behavior . 75 3.2.2.3 Stress distribution in the embedded steel components . 76 3.2.2.4 Cracking propagation 77 3.3 Phase-2—four point bending test 80 3.3.1 Stage-1—test up to service moment 80 3.3.2 Stage-2—deconstruction and reconstruction . 81 3.3.3 Stage-3—retest after reconstruction 86 3.3.3.1 Performance of specimens after reconstruction 86 3.3.3.2 Influence of presence of additional continuity rebars . 89 3.3.3.3 Influence of beam depth 90 3.3.3.4 Influence of span extension unit . 91 3.4 Phase-3—cantilever pushover test 93 iv Designing Moment-Resisting Connection for Disassembly for Implementation in Precast Reinforced Concrete Structure 3.4.1 Specimen and test setup . 94 3.4.2 Results and discussions 99 3.4.3.1 Flexural strength . 99 3.4.3.2 Deformation and ductility . 101 3.4.3.3 Energy dissipation capacity 102 3.4.3.4 Crack propagation and internal stress distribution 104 3.4.3.5 Stiffness analysis . 107 3.5 Concluding remarks 108 CHAPTER FINITE ELEMENT ANALYSIS FOR OF THE PROPOSED DFD M-R CONNECTIONS 112 4.1 Introduction . 112 4.2 Finite element modeling . 113 4.2.1 Overview 113 4.2.2 Material constitutive models 114 4.2.2.1 Steel components 114 4.2.2.2 Concrete and mortar 116 4.2.3 Boundary conditions 118 4.2.4 Solution convergence . 119 4.2.4.1 Newton-Raphson method 119 4.2.4.2 Riks method 120 4.2.4.3 Solutions to improve the analysis convergence 120 4.3 Calibration of proposed FEM . 122 v Designing Moment-Resisting Connection for Disassembly for Implementation in Precast Reinforced Concrete Structure 4.3.1 General comparison . 122 4.3.2 Influence of concrete element types 123 4.3.3 Influence of mesh schemes 124 4.3.4 Influence of tensile fracture energy . 125 4.4 Further validation of FEM 126 4.4.1 A-series specimens . 126 4.4.2 B-series specimens . 129 4.4.3 WP-series specimen . 131 4.4.4 Summary of further validation of FEM . 132 4.5 Numerical investigation of internal stress distribution . 134 4.5.1 Stress distribution of the A-series specimens . 134 4.4.2 Stress distribution of the B-series specimen 136 4.4. Stress distribution of the WP-650 specimen . 138 4.4.4 Cracking propagation comparison . 140 4.6 Conclusions . 142 CHAPTER PERFORMANCE OF THE PROPOSED DFD M-R CONNECTION WHEN USED AS PART OF A STRUCTURAL FRAME . 144 5.1 Introduction . 144 5.2 Numerical investigation on a determined H-subframe model incorporating the proposed DfD connection . 147 5.2.1 Considerations for determining the frame model 147 5.2.2 Finite element modeling of the sub-frame models 155 vi Designing Moment-Resisting Connection for Disassembly for Implementation in Precast Reinforced Concrete Structure 5.2.3 Results and discussion . 159 5.2.3.1 Sub-frame models subjected to UDL 159 5.2.3.2 Sub-frame models subjected to unidirectional lateral load . 165 5.2.3.3 Sub-frame models subjected to reverse cyclic lateral load . 170 5.3 Parametric study of main design parameters of the proposed DfD M-R connections . 173 5.3.1 Influence of endplate thickness at connection level . 173 5.3.2 Influence of bolt grades at connection level 175 5.3.3 Influence of endplate thickness and bolt grade at the sub-frame level 177 5.4 Influence of void at the connection region . 181 5.4.1 Proposed model of DfD connections with void . 181 5.4.2 Analyses of the connection itself with voids 182 5.4.3 Analyses at the sub-frame level . 185 5.5 Investigation on damage occurring during deconstruction—a conceptual analysis of pull out pre-embedded anchors . 189 5.6 Conclusions . 196 CHAPTER CONCLUSIONS AND FUTURE WORK . 200 6.1 Proposal and experimental investigation of a DfD moment-resisting connection 200 6.2 Finite element analysis for further study on the proposed DfD M-R connections 202 6.3 Study on the performance of the proposed DfD connection when used as part of a structural H-frame . 202 6.4 Recommendation for future study 205 vii Designing Moment-Resisting Connection for Disassembly for Implementation in Precast Reinforced Concrete Structure 18. 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Materials and Structures 20(2): 103-110. 212 Designing Moment-Resisting Connection for Disassembly for Implementation in Precast Reinforced Concrete Structure APPENDIX A A.1 Theoretical calculation of the moment resistance of the proposed DfD M-R connection Symbols definitions af Effective throat thickness of weld between endplate and flange ac Effective throat thickness of weld between web and endplate tw Endplate thickness m Distance between the tip of web weld and the centre of bolt (Fig. A. 1) mx Distance between the tip of flange weld and the centre of bolt (Fig. A.3) n Lesser of e and 1.25m e Distance between the centre of bolt and the side edge of the endplate (Fig. A.1) ex Distance between the centre of bolt and the top edge of the endplate g Distance between the centres of bolts (Fig. A.1) 213 Designing Moment-Resisting Connection for Disassembly for Implementation in Precast Reinforced Concrete Structure A.1.1 A500 connection Fig A.1 A500 connection geometry Connection geometry (Fig A.1) m  g /  tw /  0.8ac =170/2-6/2-0.8×1.414×6=75mm e=40mm n=min(e,1.25×m)=40mm m2=30-0.8×1.414×12=16.4mm Potential force resistance of bolts in tension zone Bolt row 214 Designing Moment-Resisting Connection for Disassembly for Implementation in Precast Reinforced Concrete Structure Calculate effective length of T-stubs. The following equations come from the design Table 6.6 as per SS EN 1993-1-8 (2010). Leff is the minimum of:  m=471mm* (* means control)  m =6.64×75=499mm Calculate Mp for the endplate Mp= Leff  te2  fu / =12796kNmm (Refer to Eq. 2.2 in Chapter 2) Mode 1: FT ,1, Rd  4M p / m =682kN (Refer to Eq. 2.2 in Chapter 2) Mode 2: FT ,1, Rd  (2M p  n F t , Rd ) / (m  n) =345kN* (Refer to Eq. 2.3 in Chapter 2) Mode 3: FT ,1, Rd   Ft , Rd =353kN (Refer to Eq. 2.4 in Chapter 2) Bolt row Row alone Calculate effective length of T-stubs. From table 6.6 as per SS EN 1993-1-8 (2010), Leff is the minimum of:  m=471mm 4m+1.25e=350mm* Mp= Leff  te2  fu / =9509kNmm Mode 1: FT ,1, Rd  4M p / m =507kN 215 Designing Moment-Resisting Connection for Disassembly for Implementation in Precast Reinforced Concrete Structure Mode 2: FT ,1, Rd  (2M p  n F t , Rd ) / (m  n) =288kN* Mode 3: FT ,1, Rd   Ft , Rd =353kN Row 1+2 combined Leff is the minimum of: 2× (  m+p)=472mm*  m +p=559mm Calculate Mp for the endplate Mp= Leff  te2  fu / =12839kNmm Mode 1: FT ,1, Rd  4M p / m =683kN Mode 2: FT ,1, Rd  (2M p  n F t , Rd ) / (m  n) =468kN* Mode 3: FT ,1, Rd   Ft , Rd =706kN Therefore the potential force resistance of each bolt in tension is: Row 1:FT1,Rd=345kN Row 2:FT,2,Rd=min(468-288)=180kN Moment resistance of A500 connection Force equilibrium equation is: concrete compression force=bolt tension force Fcc=Fst (Fig A.2) 216 Designing Moment-Resisting Connection for Disassembly for Implementation in Precast Reinforced Concrete Structure 0.85 f ck c n  (0.8 x)  b   Fti , Rd (Refer to Eq. 2.5 in Chapter 2) i 1 x=62.8mm z1=380-0.4x=354mm z2=320-0.4x=294mm n M Rd   zi  Fti , Rd =(345×354+180×294)/1000=175kNm (Refer to Eq. 2.6 in Chapter i 1 2) Fig A.2 Force equilibrium for moment resistance calculation of A500 connection 217 Designing Moment-Resisting Connection for Disassembly for Implementation in Precast Reinforced Concrete Structure A.1.2 B500 connection Fig A.3 B500 connection geometry Connection geometry (Fig A.3) mx  40  0.8a f =40 -0.8×1.414×12=26.4mm ex=40mm n=min(e,1.25×mx)=33mm Potential force resistance of bolts in tension zone Bolt row Calculate effective length of T-stubs. From table 6.6 as per SS EN 1993-1-8 (2010), Leff is the minimum of:  mx=165mm 218 Designing Moment-Resisting Connection for Disassembly for Implementation in Precast Reinforced Concrete Structure  mx+g=199mm  mx+2e=163mm mx+1.25ex=156mm e+2mx+0.625ex=118mm 0.5bp=110mm* 0.5g+2mx+0.625ex=163mm Calculate Mp for the endplate Mp= Leff  te2  fu / =2988kNmm (Refer to Eq. 2.2 in Chapter 2) Mode 1: FT ,1, Rd  4M p / m =452kN (Refer to Eq. 2.2 in Chapter 2) Mode 2: FT ,1, Rd  (2M p  n F t , Rd ) / (m  n) =296kN* (Refer to Eq. 2.3 in Chapter 2) Mode 3: FT ,1, Rd   Ft , Rd =353kN (Refer to Eq. 2.4 in Chapter 2) Bolt row Calculate effective length of T-stubs. From table 6.6 as per SS EN 1993-1-8 (2010), Leff is the minimum of:  m=471mm*  m =6.64×75=499mm Calculate Mp for the endplate Mp= Leff  te2  fu / =12796kNmm Mode 1: 219 Designing Moment-Resisting Connection for Disassembly for Implementation in Precast Reinforced Concrete Structure FT ,1, Rd  4M p / m =682kN Mode 2: FT ,1, Rd  (2M p  n F t , Rd ) / (m  n) =345kN* Mode 3: FT ,1, Rd   Ft , Rd =353kN Moment resistance of B500 connection Force equilibrium equation is: concrete compression force=bolt tension force+ tie bar tension force Fcc=Fst+Ftie (Fig A.4) 0.85 f ck c n  (0.8 x)  b   Fti , Rd (Refer to Eq. 2.5 in Chapter 2) i 1 x=87mm z1=330-0.4x=296mm z2=250-0.4x=216mm z3=500-53-0.4x=413mm n M Rd   zi  Fti , Rd =191kNm (Refer to Eq. 2.6 in Chapter 2) i 1 220 Designing Moment-Resisting Connection for Disassembly for Implementation in Precast Reinforced Concrete Structure Fig A.4 Force equilibrium for moment resistance calculation of B500 connection A.2 Full data of experimental test A full set of the experimental test results in terms of moment vs. mid-span deflection of the four-point-bending test specimens and in terms of load vs. beam tip displacement of the cantilever push-over test specimens were included in this section. As shown in Fig A.5, A500-1 and A500-2 for example refers to two identical specimens tested. 221 Designing Moment-Resisting Connection for Disassembly for Implementation in Precast Reinforced Concrete Structure A.2.1 Additional result plots of four-point-bending test Fig A.5 All result of test specimen type A500 (the specimen failed prematurely due to weld fracture failure) Fig A.6 All result of test specimen type B500 (the specimens failed prematurely due to weld fracture failure) 222 Designing Moment-Resisting Connection for Disassembly for Implementation in Precast Reinforced Concrete Structure A.2.2 Additional result of cantilever push-over test Fig A.7 Hysteretic curves of A500 test specimen Fig A.8 Hysteretic curves of B500 test specimen Fig A.9 Hysteretic curves of A650 test specimen 223 Designing Moment-Resisting Connection for Disassembly for Implementation in Precast Reinforced Concrete Structure Fig A.10 Hysteretic curves of B650 test specimen Fig A.11 Hysteretic curves of WP650 test specimen 224 [...]... discussion in the 6 Designing Moment- Resisting Connection for Disassembly for Implementation in Precast Reinforced Concrete Structure later sections, DfD M-R connections have to be designed with the provision for access for disassembly Thus such connections must cater for ease of disassembly without damage to the precast DfD structural components framing into the joint In addition, the connection must... in this case Again, the DfD connection was deemed to possess little moment resistance 8 Designing Moment- Resisting Connection for Disassembly for Implementation in Precast Reinforced Concrete Structure Fig 1.1 Details of demountable connection used in Munich’s airport (Gandler, 1985) Similar DfD connections were applied successfully in the ERGON precast industry building system in the Netherlands in. .. sustainable construction strategies in the building industry have been developed along three main fields: sustainability of concrete (John, 2003), sustainable construction methods (Palaski, 2004), and design for deconstruction (Guy et al, 2002; Kiber, 2003; Chini, 2005) Sustainability of 1 Designing Moment- Resisting Connection for Disassembly for Implementation in Precast Reinforced Concrete Structure concrete. .. result plots of four-point-bending test 222 A.2.2 Additional result of cantilever push-over test 223 viii Designing Moment- Resisting Connection for Disassembly for Implementation in Precast Reinforced Concrete Structure SUMMARY Application of DfD (Design for Disassembly) concepts in the building industry has gained world-wide research interest in recent years due to its inherent benefits both... beam-column connection in ERGON system (Acker, 1985) 9 Designing Moment- Resisting Connection for Disassembly for Implementation in Precast Reinforced Concrete Structure The above mentioned DfD connections using threaded bars or rods with end nut anchorages were later widely applied in the construction of precast concrete structures The DfD connection was also extended for use in wall panel joints, column-column... the 2 Designing Moment- Resisting Connection for Disassembly for Implementation in Precast Reinforced Concrete Structure structural components are designed to be deconstructed and reused for a second cycle application 1.1.2 Design for Disassembly (DfD) Design for Deconstruction (DfD) is an emerging concept that borrows from the fields of design for disassembly, reuse, remanufacturing and recycling in the... and panel system 7 Designing Moment- Resisting Connection for Disassembly for Implementation in Precast Reinforced Concrete Structure in which special fasteners were used to form the pinned connection to facilitate the subsequent dismantlement Although the precast building has proved the success of disassembly and re-assembly, it is clear that the connections used did not provide moment resistance and... tension q Uniformly distributed load applied along the beam t Endplate thickness w Crack opening wl  G f / f ct corresponding to  ct  0.2 f ct z Lever arm between the center of bolt row and compression concrete c Concrete compression strain  cl Strain at concrete maximum compressive stress xii Designing Moment- Resisting Connection for Disassembly for Implementation in Precast Reinforced Concrete Structure... Engineering strain  true Logarithmatric plastic strain p Plastic compressive strain  eng Engineering stress  true True stress  ct Concrete tensile stress u Ultimate curvature y Yield curvature  c / l  Mid-span deflection of specimen  net Net tip displacement of test specimen in push-over test xiii Designing Moment- Resisting Connection for Disassembly for Implementation in Precast Reinforced. .. order moments to beams and slabs, and hence reduce 5 Designing Moment- Resisting Connection for Disassembly for Implementation in Precast Reinforced Concrete Structure column moments; and 4 Improve resistance of skeletal frame to progressive collapse From the point view of DfD, however, current practice in precast concrete frame construction reveals that demountability is seldom an option available for . DESIGNING MOMENT- RESISTING CONNECTION FOR DISASSEMBLY FOR IMPLEMENTATION IN PRECAST REINFORCED CONCRETE BUILDINGS LIN ZHISHENG NATIONAL UNIVERSITY OF SINGAPORE. DESIGNING MOMENT- RESISTING CONNECTION FOR DISASSEMBLY FOR IMPLEMENTATION IN PRECAST REINFORCED CONCRETE BUILDINGS LIN ZHISHENG (M.Eng, SCUT) A THESIS SUBMITTED FOR. ENGINEERING DEPARTMENT OF CIVIL AND ENVIRONMENTAL ENGINEERING NATIONAL UNIVERSITY OF SINGAPORE 2013 Designing Moment- Resisting Connection for Disassembly for Implementation in Precast Reinforced