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International Concrete Abstracts Portal

Showing 1-5 of 5 Abstracts search results

Document: 

SP-333_05

Date: 

October 1, 2019

Author(s):

Ruo-Yang Wu and Chris P. Pantelides

Publication:

Symposium Papers

Volume:

333

Abstract:

Two severely damaged concrete column-to-cap beam specimens were successfully repaired, using a carbon fiber-reinforced polymer (CFRP) cylindrical shell, non-shrink repair concrete, and headed steel bars. The first cast-in-place specimen experienced concrete crushing and longitudinal bars fracture/buckling; for the second precast specimen, the column was completely separated from the cap beam. In this paper, two analytical models, Model Fiber and Model Rotational Spring (RS), simulating the seismic performance of the repaired specimens are proposed. In Model Fiber, plasticity considering bond-slip effects was distributed over the defined plastic hinge length of the nonlinear beam-column element. In Model RS, a non-linear rotational spring was used to consider the concentrated plasticity located at the repaired cross-section. Low-cycle fatigue of the damaged column longitudinal steel bars was included in the analytical models. Simulations show that the analytical results, in terms of hysteretic response and moment-rotation, are in very good agreement with the experimental results. Model fiber performed better for predicting the pinching effect in the hysteretic response of the repaired cast-in-place specimen; Model RS performed better for matching the hysteresis curves of the repaired precast concrete specimen. In addition, Model Fiber was able to predict the local response of the columns including the fracture of longitudinal bars due to low-cycle fatigue.


Document: 

SP327-29

Date: 

November 1, 2018

Author(s):

Mostafa Yossef, An Chen and Austin Downey

Publication:

Symposium Papers

Volume:

327

Abstract:

Insulated concrete sandwich panels are composed of two concrete wythes separated by an insulation layer and connected by shear connectors. This paper develops a multifunctional photovoltaic (PV) integrated insulated concrete sandwich (PVICS) panel, which can act as a passive energy system through the insulation layer and an active energy system by harvesting the solar energy using attached thin-film solar cells. The panel features an innovative co-curing scheme, where solar cells, Fiber-Reinforced Polymer (FRP) shell, and polymer concrete are manufactured together to act as a formwork for the sandwich panel. The objective of this paper is to prove the concept of PVICS based on bending test, Finite Element (FE) analysis and analytical study. It can be concluded that the test results correlate well with those from the FE and analytical models. FRP shell can act as both shear connectors and reinforcement. The panel achieved 82% Degree of Composite Action, which can provide enough strength and stiffness. Solar cells worked properly under service load. Shear-lag effect was observed for the strains along the width of the panel.


Document: 

SP326-98

Date: 

August 10, 2018

Author(s):

Francesca Albani and Carlo Dusi

Publication:

Symposium Papers

Volume:

326

Abstract:

After World War II the research about the double curvature structures in reinforced concrete was a frontier in the field of typological, spatial and expressive innovation. Among the principal leading figures was the swiss engineer Heinz Isler with his methods called “form finding” based on the use of physical modeling to determine the form and subsequently investigate its stability. When a concrete shell is shaped using a hanging-membrane model, it assumes an ideal form using a minimum of materials, with minimal deformations and in compression only. This is only the first step in the process of finding the form. Then one has to do the exact structural analysis, the layout of the reinforcement and prestressing elements, and the detailing, to deal with construction problems, and finally to carefully observe the structure in use.

The need to protect the works of Heinz Isler has slowly been bearing fruit in recent years. This highlights in a very special way the crucial point of the debate on the protection of modern and contemporary architecture: the recognition of their architectural and cultural values, and consequently the difficulties of the institutions responsible for undertaking their preservation.

The paper intends to investigate the case of the Deitingen service station built in 1968-1969 which represents a fortunate phase in this process and shows how the factors linked to the durability of structures play a small role in the decision-making processes regarding the future of these works. The key role is played by the significance and values that acquires (or loses) over time.


Document: 

SP107-03

Date: 

June 1, 1988

Author(s):

J. Zimmerman

Publication:

Symposium Papers

Volume:

107

Abstract:

Air-supported forming represents a rapid and cost-effective technique for building long span, thin shell, monolithic concrete structures. This construction method consists of inflating an air form, designed to the required building size and shape, after attachment to a foundation ring. Once inflated, the inside skin of the air form is sprayed with polyurethane foam. Steel reinforcement is fastened to the inside surface of the foam. Concrete is sprayed over the steel reinforcement, again from the inside. Steel is not placed, and concrete is not sprayed where shell openings are required. The air form can be color-coated and textured, or removed for reuse when protective coatings are applied over the exposed foam. This technology is appropriate for free-span architectural applications, bulk storage of granulated solids, and liquids.

DOI:

10.14359/3346


Document: 

SP103-06

Date: 

September 1, 1987

Author(s):

Ronald D. Guthrie, Raymound R. Funk, andEdwin G. Burdette

Publication:

Symposium Papers

Volume:

103

Abstract:

Steel embedments are utilized to transmit load from equipment, piping systems, cable trays, and similar apparatuses into reinforced concrete structures. The types of embedments or anchors may be postinstalled--such as expansion shell, wedge, undercut, and

DOI:

10.14359/1672


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