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Home > Publications > International Concrete Abstracts Portal
Showing 1-5 of 227 Abstracts search results
Document:
SP364_2
Date:
December 1, 2024
Author(s):
Youjin Chae, Min-Jun Jeon, Chang-Kil Ju, Seung-Il Kim, and Tae-Sung Eom
Publication:
Symposium Papers
Volume:
364
Abstract:
Modular construction has been attracting attention worldwide as a promising solution to reduce construction time and labor demand. In this study, a new inter-module composite floor system that connects the upper module floor beams and lower module ceiling beams was experimentally and analytically investigated with an emphasis on vibration performance under service loading. First, the upper module floor of 2 m [6.56 ft] wide and 6 m [19.7 ft] long was fabricated as a composite system consisting of precast concrete (PC) panels, steel beams and ultra high-performance concrete (UHPC) connectors. Structural integrity between PC panels, steel beams and UHPC connectors were secured using grouting and topping mortar. Then, the lower module ceiling beams were connected to the upper module floor beams by fully tensioned high-tension bolts (i.e., slip-critical connection) to complete the inter-module composite floor. The vibration frequencies, damping ratio, and acceleration responses of the inter-module composite floors were measured from laboratory tests such as impact hammer, heel drop and walking tests, considering the number and location of the connecting bolts as the test parameter. The vibration characteristics of the inter-module composite floors were investigated further through finite element analysis. The measured and predicted vibration performances were compared with the acceptance criteria in AISC Design Guide 11 and ISO 10137.
DOI:
10.14359/51745454
SP-361_06
March 1, 2024
Michelle L. Hendrickson, Christine A. Langton, and Joan Q. Wu
361
Sixty percent of the nation's highly toxic and radioactive mixed wastes are stored at Hanford in 177 deteriorating underground storage tanks. To close or remove these storage tanks from service and place them in a condition that is protective of human health and the environment, the tanks must be physically stabilized to prevent subsidence once wastes have been retrieved. Remaining residual liquid waste in the tanks that cannot be removed must be solidified and the solid wastes encapsulated to meet the Nuclear Regulatory Commission, Department of Energy, Environmental Protection Agency, and the State of Washington requirements. The Department of Energy has developed cementitious flowable concretes to restrict access and provide chemical stabilization for radionuclides. Formulation, laboratory, and field testing for application at Hanford began with flowable, self-leveling structural and non-structural fills. A slump flow equal to or greater than 610 mm, 0% bleed water, and 0.1% (by volume) shrinkage measurements were key parameters guiding reformulation efforts that resulted in highly flowable, self-consolidating concretes that met Hanford 241-C Tank closure short- and long-term regulatory and engineering performance requirements.
10.14359/51740608
SP-360_25
Francesca Ceroni, Alberto Balsamo, Marco Di Ludovico
360
Masonry structures are very sensitive to out-of-plane mechanisms under horizontal actions. A common traditional technique to avoid or mitigate the activation of these mechanisms is represented by injected anchors made of steel bars aimed to improve the connections between orthogonal masonry walls or between floors and masonry walls. The bars are usually embedded in the masonry by means of cement-based grout in holes realized inside the elements to be connected. Recently, an increased interest has developed in the scientific community about the use of Fibre Reinforced Plastic (FRP) bars as alternative to the steel ones for injected anchors, mainly because of their high tensile strength and inertia to corrosion, which can give them high durability, in addition to the use of high-performance grouts. The paper reports the results of experimental pull-out tests realized by the Authors on several types of FRP bars used as injected anchors in small masonry specimens made of yellow tuff blocks. A hydraulic lime and pozzolana-based grout is used to fix the bars in holes realized in the masonry specimens along an embedded length of 250 mm. The set-up is realized in order to apply pure tension to the bars and shear stresses along the bar-grout and the grout-masonry interfaces. The results are analysed in terms of maximum pull-out forces, failure modes and force-displacement relations in order to evidence the global performance of each tested system, especially in relation with the diameter and the surface treatment of the bars. Some comparisons with literature formulation for predicting the pull-out force are developed too.
10.14359/51740637
CI4409Q&A
September 1, 2022
Concrete International
44
Issue:
9
According to Appendix C—Alternative Load and Strength Reduction Factors in ACI 318-111 and previous versions, a load combination given by Eq. (C.9-2), U = 0.75(1.4D + 1.7L) + 1.6W, can be used for structures when service-level wind loads are used. Because this appendix was removed from ACI 318-142 and ACI 318-19,3 could these requirements still be used when designing with ACI 318-19? According to Fig. 1 (Fig. R17.10.5.3 in ACI 318-191), grout pad thickness is included when calculating stretch length. Is that correct? If using sleeves, can they be filled with grout? What is the effective depth (hef) of an anchor with a sleeve?
According to Appendix C—Alternative Load and Strength Reduction Factors in ACI 318-111 and previous versions, a load combination given by Eq. (C.9-2), U = 0.75(1.4D + 1.7L) + 1.6W, can be used for structures when service-level wind loads are used. Because this appendix was removed from ACI 318-142 and ACI 318-19,3 could these requirements still be used when designing with ACI 318-19?
According to Fig. 1 (Fig. R17.10.5.3 in ACI 318-191), grout pad thickness is included when calculating stretch length. Is that correct? If using sleeves, can they be filled with grout? What is the effective depth (hef) of an anchor with a sleeve?
SP-345_12
February 1, 2021
Xingxing Zou, Chris Moore, and Lesley H. Sneed
345
Externally bonded (EB) steel reinforced grout (SRG) composites have the potential to improve the flexural and shear performance of existing concrete and masonry structural members. However, one of the most commonly observed failure modes of SRG-strengthened structures is due to composite debonding, which reduces composite action and limits the SRG contribution to the member load-carrying capacity. This study investigated an endanchorage system for SRG strips bonded to a concrete substrate. The end anchorage was achieved by embedding the ends of the steel cords into the substrate. Nineteen single-lap direct shear specimens with varying composite bonded lengths and anchor binder materials were tested to study the effectiveness of the end-anchorage on the bond performance. For specimens with relatively long bonded length, the end-anchorage slightly improved the performance in terms of peak load achieved before detachment of the bonded region. Anchored specimens with long bonded length showed notable post-detachment behavior. Anchored specimens with epoxy resin achieved load levels significantly higher than the peak load before composite detachment occurred. For specimens with relatively short bonded length, the end-anchorage provided a notable increase in peak load and global slip at composite detachment. A generic load response was proposed for SRG-concrete joints with end anchors.
10.14359/51731578
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