Toward a consistent design of structural concrete

A proposed supplement to ASCE/SEI 41 Seismic Rehabilitation of Existing Buildings has been developed for the purpose of updating provisions related to existing reinforced concrete buildings. Based on experimental evidence and empirical models, the proposed supplement includes revisions to modeling parameters and acceptance criteria for reinforced concrete beams, columns, structural walls, beam-column joints, and slab-column frames. The revisions are expected to result in substantially more accurate and, in most cases, more liberal assessments of the structural capacity of concrete components in seismic retrofit projects. DOI: 10.1193/1.2757714

Update to ASCE/SEI 41 Concrete Provisions

The City of Los Angeles, the City and County of San Francisco, and other communities on the West Coast are undergoing a boom in the construction of high-rise buildings that involve a variety of unusual configurations, innovative structural systems, and high performance materials. Various jurisdictions, with the active involvement of peer review committees, are considering performance-based methods to assess the adequacy of these new designs. These parallel efforts create a timely opportunity for collaboration to improve and increase the application of performance-based designs for tall buildings, thereby assuring that new high-rise construction meets intended safety and performance objectives, ensuring safe and usable buildings after future major earthquakes. The Pacific Earthquake Engineering Research Center (PEER) is presently undertaking a multiyear program to develop guidelines to aid the engineering community with the design, analysis and construction of these tall buildings.

ATC-72 of the PEER Tall Buildings Initiative: Interim Guidelines on Modeling and Acceptance Criteria for Seismic Design and Analysis of Tall Buildings

A softened strut-and-tie model for determining the shear strength of squat walls is proposed in this paper. The proposed model originates from the strut-and-tie concept and satisfies equilibrium, compatibility, and constitutive laws of cracked reinforced concrete. The shear capacities of 62 squat walls were calculated and compared with the available experimental results, and reasonable agreement was obtained. Based on the collected experimental data in this paper, the proposed physical model was used to study the effects of boundary elements, cyclic loading, and vertical loads on the wall shear strength. The softened strut-and-tie model can be further developed to improve the current shear wall design procedures by incorporating the actual shear resisting mechanisms in predicting shear strength of walls.

Analytical model for predicting shear strength of squat walls

https://rosap.ntl.bts.gov/view/dot/957/dot_957_DS1.pdf

Behavior of Field-Cast Ultra-High Performance Concrete Bridge Deck Connections Under Cyclic and Static Structural Loading

Strength of Low-Rise Structural Walls

The stress range to which a reinforcing bar is subjected is the primary factor determining its fatigue life. For design purposes, there is a limiting stress range, the fatigue limit, above which a reinforcing bar will have a finite fatigue life and is certain to fracture. At stress ranges below the fatigue limit, a reinforcing bar will have a long fatigue life and may be able to sustain a virtually unlimited number of stress cycles. The magnitude of the fatigue limit depends on the minimum stress during each stress cycle and on the shape of the deformatins rolled onto the bar surface. It may also depend on the diameter and the grade of the bar. Increasing a tensile minimum stress was found to result in a decrease in fatigue strength. On the other hand the fatigue was found to incrase with an increasing compressive minimum stress. Bar diameter and grade of bar were found to influence the finite-life fatigue strength of reinforcing bars. The existence of a long-life fatigue effect due to these variables could not be established. Larger size bars have a lowered fatigue strength while higher grade bars have an increased fatigue strength. The effect of lug geometry on fatigue strength was found to be coupled with that of bar diameter. The larger the bar diameter, the greater was the effect of lug geometry.

Fatigue strength of high-yield reinforcing bars

Time Dependent Deformations in a 70 Story Structure

DESCRIBED ARE THE DETAILS OF MAKING AND TESTING A 1/10-SCALE MODEL OF A PROPOSED THREE-SPAN BRIDGE FOR WASHINGTON, D. C., THAT WOULD BE ONE OF THE WORLD'S LONGEST PRESTRESSED CONCRETE CANTILEVER TYPE BRIDGES WHEN COMPLETED. TEST RESULS ARE GIVEN THAT SHOW SUITABILITY OF DESIGN AND CONFORMANCE WITH SPECIFICATIONS. /JPCI/

W G Corley

Papers

Strength of Low-Rise Structural Walls

Fatigue strength of high-yield reinforcing bars

Time Dependent Deformations in a 70 Story Structure

Design ultimate load test of 1/10-scale micro-concrete model of new potomac river crossing, i-266