Email Address is required Invalid Email Address
In today’s market, it is imperative to be knowledgeable and have an edge over the competition. ACI members have it…they are engaged, informed, and stay up to date by taking advantage of benefits that ACI membership provides them.
Read more about membership
Learn More
Become an ACI Member
Founded in 1904 and headquartered in Farmington Hills, Michigan, USA, the American Concrete Institute is a leading authority and resource worldwide for the development, dissemination, and adoption of its consensus-based standards, technical resources, educational programs, and proven expertise for individuals and organizations involved in concrete design, construction, and materials, who share a commitment to pursuing the best use of concrete.
Staff Directory
ACI World Headquarters 38800 Country Club Dr. Farmington Hills, MI 48331-3439 USA Phone: 1.248.848.3800 Fax: 1.248.848.3701
ACI Middle East Regional Office Second Floor, Office #207 The Offices 2 Building, One Central Dubai World Trade Center Complex Dubai, UAE Phone: +971.4.516.3208 & 3209
ACI Resource Center Southern California Midwest Mid Atlantic
Feedback via Email Phone: 1.248.848.3800
Home > Publications > International Concrete Abstracts Portal
The International Concrete Abstracts Portal is an ACI led collaboration with leading technical organizations from within the international concrete industry and offers the most comprehensive collection of published concrete abstracts.
Showing 1-5 of 20 Abstracts search results
Document:
SP86-06
Date:
August 1, 1985
Author(s):
Maher K. Tadros and Amin Ghali
Publication:
Symposium Papers
Volume:
86
Abstract:
A manual calculation procedure is presented for predic-tion of deflection of partially prestressed beams. Adequate accur-acy is achieved by accounting for the important parameters affecting the deflection: creep and shrinkage of concrete, relaxation of pre-stressed steel, cross section areas and locations of prestressed and nonprestressed steel and cracking at the sections where the tensile strength of concrete is exceeded. Design aids are presented to sim-plify calculation of properties of cracked sections. Numerical exam-ples are included.
DOI:
10.14359/6429
SP86-07
Cameron J. Graham and Andrew Scanlon
The effect of construction loading on deflection of flat plate slabs is investigated. Progressive cracking, as load is incremented to the shored slab, is included in the finite element analysis for instantaneous deflections. Individual creep curves that reflect the loading age of concrete are superimposed to obtain total creep deflections. Overall long-time deflections also include shrinkage effects. Results calculated for a multistory flat plate structure are in good agreement with a set of measured one-year deflections.
10.14359/6430
SP86-14
Dan E. Branson and A. Fattah Shaikh
Unified procedures for computing the deflection (using Ie) and centroidal axis location (using a,) of nonprestressed and partially prestressed members under short-term loading are presented. These procedures include the average effects of tension stiffening and the random distribution of cracks along a member. Also included is the simplified Ie method adopted for the ACI Code (R/C) and PCI Handbook (P/C) since 1971, and AASHTO (R/C) since 1973; as well as the proposed Australian Concrete Code and the PCA Notes on the 1983 ACI Building Code for both nonprestressed (R/C)and partially prestressed (P/C) members. The unified I, method is based on the zero deflection point as the reference, whereas the simplified Ie, method for prestressed members is based on computing the live load deflection increment from the 'prestress camber' -minus - 'dead load deflection' point. Results by the two Ie methods are shown to be in relatively close agreement. A comparison is made between the centroidal axis location (ae d), based on an empirically determined average effective partially cracked section; and the theoretical centroidal axis location (c1), as determined by Nilson for the maximum tensile stress section. The results are thought to be reasonable. For computing long-term camber and deflection, a simple multiplier method used in the PCI Design Handbook, and a somewhat more detailed multiplier method used by ACI Committee 435 since 1963 and also used in the PCA Notes on the 1983 ACI Building Code, are applied to partially prestressed members. Results by the two methods are shown to be comparable.
10.14359/6437
SP86-02
ACI Committee 435
This report is in two distinct parts. Part I is a summary of published studies on slab deflections (3 from Australia, 1 from Scotland, 1 from Sweden, 2 from U.S.). The summary focuses on construction practices and materials quality. Comparison of deflections calculated by various methods with actual long-term deflections is made in some cases. Part II summarizes several construction problems and mate-rial deficiencies which can contribute to large long-term deflec-tions. Focusing on large construction loads, the authors show
10.14359/6425
SP86-10
A. E. Aktan, V. V. Bertero, and K. Sakino
The lateral stiffness characteristics of medium-rise frame-wall systems were investigated at the serviceability limit state. Physical models of two exemplary structures, as well as individual wall elements, were tested. Experimentally measured displacements, local distortions, and internal force distributions were observed to differ by more than 100 percent from the analytically generated ones. The flexural, shear, and axial stiffnesses of individual wall elements were observed: (1) to be strongly influenced by intensity of axial force, (2) to approach nominal values based on gross-transformed section properties only at axial compression levels nearing the balanced value in the wall axial-flexural strength interaction relationship, (3) to decrease to less than 20 percent of the nominal stiffnesses at axial force levels approaching zero, and (4) to degrade significantly upon cracking at the serviceability limit state. Microcracking and very narrow cracking due to shrinkage induced by volumetric changes were identified as the main factors leading to reduced stiffnesses of walls upon first loading.
10.14359/6433
Results Per Page 5 10 15 20 25 50 100