1、 I AC1 SP-Lob 8 0bb2749 0003bOL m L. COMPERAPPLCATIONS IN CONCRETE TECHNOLOGY San Antonio 1987 i0000000000000000000000000000000000000000000000000000000000000000000000 i0000000000000077777777777ooooooooooooooaooooooooooooooooooooooooooooooc l00000c00000777777777777777700000000000000000000000000000000
2、0000000000c i000000000007777777777777777777000U000000000077770000000000000000000000C 10000000000077777777777777777777000000000007777777700000000000000000000C 10000000000007777777777777777770000000000077777777777000000000000000000 10000000000000077777777777777700a0000000777777777777770000000000000000
3、c I0000000000000000777777777770000000000077777777777777700000000000000000C IOOOOO00000000000007777777700000000000777777777777777000000000000000000 10000000000000000000000000000000000000777777777777770000000000000000000 10000000000000000000000000000000000000077777777777700000000000000000000c 10000000
4、000000000000000000000000000000007777777777000000000000000000000 1000000000000000000000000000000000000000077777770000000000000000000000 10000000000000044444444000000000000000000007777700000000000000000000000L 10000000000004444444444440000000000000000000000000000000000000000000000c 1000000000004444444
5、4444400000000000000000000000000000000000000000000000c 10000000000444444444444444000000000000000000000000000000000000000000000c 10000000000444444444444444440000000000000000000000000000000000000000000c 10000000004444444444444444440000000000000000000000000000000000000000000c 100000000004444444444444444
6、00000000000000000000000000000000000000000000C 10000000000044444444444444000000000000000000000000000000000000000000000 oooooooooooooooooooooooooooooooooooooooooooooooooooooooooooor 10000000000000044444440000000000000000000000000000000000000000000000000r 10000000000000000000000000000000000000000000000
7、000000000000000000000000 10000000000000000000000000000000000000000000000000000000000000000000000r 1OOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOObbbbbbbOOOOO lOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOObbbbbbbbbbOOO lOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOObbbbbb
8、bbbbbOOOOO lOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOObbbbbbbbbbbbOOOOOO OOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOObbbbbbbbOOOOOOOO 100000000000000000000000000000000000000000000000000000000a0000000000000 Victor E. Saouma Editor SP-106 eflm American Concrete Institute, Detroit A
9、C1 SP-106 8 W Obb23q9 0003b02 T - _ DISCUSSION of individual papers in this symposium may be submitted in accordance with general requirements of the AC1 Publication Policy to AC1 headquarters at the address given below. Closing date for submission of discussion is December 1, 1988. All dis- cussion
10、 approved by the Technical Activities Committee along with closing remarks by the authors will be published in the May-June 1989 issue of either AC1 Structural Journal or AC1 Materials Journal depending on the subject emphasis of the individual paper. The Institute is not responsible for the stateme
11、nts or opinions expressed in its publications. able to, nor intended to, supplant individual training, responsi- bility, or judgment of the user, or the supplier, of the informa- tion presented. Institute publications are not The papers in this volume have been reviewed under Institute publication p
12、rocedures by individuals expert in the subject areas of the papers. Copyright I988 AMERICAN CONCRETE INSTITUTE P.O. Box 191 50, Redford Station Detroit, Michigan 4821 9 All rights reserved including rights of reproduction and use in any form or by any means, including the making of copies by any pho
13、to process, or by any electronic or mechanical device, printed or written or oral, or recording for sound or visual reproduction or for use in any knowledge or retrieval system or device, unless permission in writing is obtained from the copyright proprietors. Printed in the United States of America
14、 Editorial production: Patricia J. Kost LIBRARY OF CONCRESS CATALOG CARD NUMBER 88-70140 The primary goal of AC1 Committee 118, Use of Computers, is to provide a forum for the presentation and dissemination of in- formation pertaining to recent computer related developments which can be of practical
15、 use to the engineering community. is accomplished by sponsorship of technical sessions at the Annual AC1 conventions and at committee meetings during AC1 conventions. Dissemination is achieved primarily through AC1 special publica- tions, such as this one. Presentation In reporting practical applic
16、ations, many of the papers re- present a technique or method which has been under investigation for years, and which has finally reached a degree of maturity which lends it to a practical application. As such, it should come as no surprise if depth coverage gave way to breadth of applications, and i
17、f theory is overshadowed by applications. This volume contains the full length papers which were pre- sented at the San Antonio AC1 convention in March 1987. Each author is gratefully acknowledged not only for contributing his paper, but also for reviewing another one. Finally, special thanks should
18、 be extended to William Price for providing the leadership and guidance which were essential for the success of our committee. Victor E. Saouma Committee 118 . 111 AC1 Committee 118 USE OF COMRJTERS William A. Price Chairman Robert P. Barnett Mohammad A. Bhatti Omar D. Cardona Steven R. Close Benjam
19、in Colucci Roselle Drahushak-Crow Fernando E. Fagundo Fouad H. Fouad Geoffrey Frohnsdorff Thomas E. Gates Shlomo Ginsburg Joseph D. Glikin Ans J. Helou Jorge Hidalgo Jose M. Izquierdo Milind R. Joglekar Milo S. Ketchum David G. Kittridge David B. Lewis James R. Libby A. Murray Lount William E. McDon
20、ald Carl P. Meglan Christian Meyer Jose G. Olrneda-Lopez Shriniwas N. Pagay Richard A. Parmelee William W. Payne, Jr. Andrei M. Reinhorn Stephen G. Ridge Victor E. Saouma Sidney H. Simmonds Julian Snyder Roger R. Takacs Michael A. Taylor Terence A. Weigel Thomas H. Wenzel o CONTENTS PREFACE . iii CO
21、MPUTER ANALYSES OF TIME-DEPENDENT BEHAVIOR OF CONTINUOUS PRECAST PRESTRESSED BRIDGES by J.D. Glikin, S.C. Larson, and R.G. Oesterle 1 SUBSTRUCTURE MODELING OF TWO-WAY SLAB SYSTEMS by M. Hoit, F. Fagundo, and T. Hamilton 25 PREDICTION OF SHEAR FAILURE IN CONCRETE STRUCTURES USING NONLINEAR FINITE ELE
22、MENT ANALYSIS P by R.H. Iding, B. Bresler, and S.P. Dawson . 47 MAINTENANCE AND IMPLEMENTATION OF AN EXPERT SYSTEM FOR DURABLE CONCRETE By L.J. Kaetzel and J.R. Clifton .75 AN ELECTRONIC BULLETIN BOARD SYSTEM (BBS) AT THE NATIONAL SOCIETY OF PROFESSIONAL ENGINEERS by J. Pepper . 87 A PROGRAMMING ENV
23、IRONMENT FOR STRUCTURAL ENGINEERING APPLICATIONS BASED ON INTERACTIVE COMPUTER GRAPHICS by C.I. Pesquera . 99 COMPUTER-AIDED DESIGN TOOLS IN THE CORPS FOR CONCRETE STRUCTURES by N. Radhakrishnan and R.J. Smith . .lo9 RESEARCH IN COMPUTER AIDED DESIGN OF REINFORCED CONCRETE AT THE UNIVERSITY OF COLOR
24、ADO by V.E. Saouma, S. Doshi, M.S. Jones, and E.S. Sikiotis. . .i25 AN AUTOMATIC QUANTITATIVE IMAGE ANALYSIS SYSTEM FOR CEMENT AND CONCRETE RESEARCH by D. Shi . I39 A THREE-DIMENS IONAL STAB1 L ITY ANALY S I S/DESIGN ( 3DSAD) COMPUTER PROGRAM FOR CONCRETE MONOLITHIC STRUCTURES by F.T. Tracy. 159 SI
25、(Metric) TABLES 177 INDEX . 179 V Computer Analyses of Time-Dependent Behavior of Continuous Precast Prestressed Bridges by J.D. Glikin, S.C. Larson, andR.G. Oesterle Synopsis: Design and construction of bridges composed of simple-span, pretensioned girders made continuous for composite dead and liv
26、e loads have become widespread. The design of these structures in the United States has been generally based on the procedure outlined in “Design of Continuous Highway Bridges with Precast, Prestressed Concrete Girders,Il published by the Portland Cement Association (PCA) in 1969. Although existing
27、bridges designed by this procedure are generally performing well, it is believed that this method may not accurately predict the true behavior of these structures. One of the major uncertainties in the design of these structures is prediction of positive and negative moments in the cast-in-place con
28、nections at the piers. This uncertainty is due to the different loading and construction stages, time- dependent effects, and details used to make the connections. To resolve such uncertainties, Construction Technology Laboratories, Inc. has conducted an analytical study under the sponsorship of the
29、 National Cooperative Highway Research Project 12-29. The objective was to develop guidelines for more rational design of the continuity connections. This paper summarizes results of an extensive parametric study to consider the effects of- (1) construction sequence including simple span behavior be
30、fore and continuous behavior after casting the deck and diaphragms, (2) time-dependent behavior including concrete creep and shrinkage, and steel relaxation, (3) live load applied at any stage of service life, (4) cracking resulting from both positive and negative moment including Itension stiffened
31、“ stress-strain relationships for reinforcement, and (5) closing of cracks when combined dead load plus time-dependent moments are reversed by application of live loads. Keywords: bridges (structures) ; computer programs; continuity 7structuralI ; cracking (fracturing); creep properties; girders; lo
32、ads (forces) ; moments; precast concrete; prestressed concrete;. pretensioning ; shrinkage; stress relaxat ion ; structura 1 analysis 1 Joseph D. Glikin is Senior Structural Engineer of Analytical Design Section, Structural Development Department, Construction Technology Laboratories, a Division of
33、the Portland Cement Association, Skokie, Illinois. Dr. Glikin is the author of about 40 technical papers related to the structural mechanics, computer application, optimal design, inelastic behavior of reinforced concrete, foundations and suspension cable systems. AC1 member Ralph G. Oesterle, is Ma
34、nager, Analytical Design Section, Structural Development Department, Construction Technology Laboratories, Inc, a Division of Portland Cement Association, Skokie, Illinois. He received his Ph.D from the Northwestern University, Evanston. His research primarily concerns the inelastic behavior of rein
35、forced concrete elements. Steven C. Larson is Engineer, Structural Analytical Section, Structural Engineering Department, Construction Technology Laboratories, Inc., Skokie, Illinois. His work primarily consists of analytical studies and evaluation of reinforced and prestressed concrete structures.
36、INTRODUCTION Bac kciround Application of precast, prestressed girders to bridge construction started in the United States in the early 1950s. Use of pretensioned I-girders with cast-in-place concrete decks grew rapidly. Until the early 1960s, bridges built with pretensioned I-girders and cast-in-pla
37、ce concrete deck were designed as simply supported spans. However, longitudinal reinforcement placed in continuous deck slabs above the piers provided negative moment capacity. Therefore, these I-girders could be considered as partially continuous for negative moments at the piers. The degree of con
38、tinuity depends on the time-dependent effects and the positive and negative moment connection details provided at the piers. In a pretensioned member, prestress will usually cause the member to camber. If the member is simply supported, the ends of the member will tend to rotate, as shown in Fig. l(
39、a). When members are made continuous through the deck and pier diaphragms, the ends of the pretensioned girder are restrained from rotating. As a result, a positive restraint moment, as shown in Fig. l(b) may occur at the pier. Positive moment also occurs at the piers when alternate spans have live
40、loads. Reinforcement for positive moment connection is designed for Computer Applications 3 the summation of positive moment due to time-dependent effects and live load application. Construction of the positive moment connection detail is generally expensive and time consuming. In 1961, the Portland
41、 Cement Association (PCA) conducted an experimental research program on this type of bridge (1). The research program studied the influences of creep in the precast girders and differential shrinkage between the precast girders and the cast-in-place deck slab on continuity behavior after an extended
42、 period of time, As a result of these studies, procedures were developed for design of the positive moment connection and the negative moment reinforcement over supporting piers (2). There are several uncertainties associated with the PCA procedures. Some of the uncertainty stems from the simplifyin
43、g assumptions made in the PCA procedures. One assumption is that girder concrete and deck concrete have the same creep and shrinkage properties. This would not generally be the case, particularly if the sequence of construction results in significantly different ages between the girder, diaphragm, a
44、nd deck concrete. Different concrete mixes and curing conditions for girder, diaphragm, and deck concretes also cause differences in creep and shrinkage properties. Also, for the PCA simplified analyses, the continuity connections are considered to have zero length and to be fully rigid. Full contin
45、uity is assumed in calculation of live-load positive and negative moments. The actual connections have finite lengths and rotational stiff- nesses. The moment of inertia of the reinforced concrete section at the connection after cracking from either positive or negative moment will be significantly
46、lower than the prestressed girder section. In addition, when positive restraint moment from time-dependent effects causes cracking in the diaphragm concrete, these cracks must close before the full section becomes effective for negative live load moment. NCHRP Project 12-29 Since the PCA research wa
47、s completed over 20 years ago, there have been significant advancements in understanding of material behavior and in methods of analysis. Therefore, CTL is conducting NCHRP Project 12-29 to investigate the behavior of precast, prestressed girders made continuous and to develop guidelines for determi
48、ning design moments commensurate with the degree of continuity developed at the piers. From a questionnaire survey carried out as a first task to Project 12-29, it was learned that there is significant variation in application of this type of bridge design by various state Departments of Transportat
49、ion. This is particularly true with respect to the positive moment design of the continuity connection. Current practice includes: 4 Glikin, Larson, and Oesterle Designing and providing positive moment reinforcement or using standard details at the pier connection and considering negative moment continuity for reduction of live load positive moment near midspan. Designing and providing positive moment reinforcement or using standard details but ignoring negative moment continuity for red
