International Concrete Abstracts Portal

Showing 1-5 of 416 Abstracts search results

Document: 

CI4704Bischoff

Date: 

April 1, 2025

Author(s):

Peter H. Bischoff

Publication:

Concrete International

Volume:

47

Issue:

4

Abstract:

This is the third article in a five-part series. While Parts 1 and 2 review the procedure and basis for computing deflection of reinforced concrete with a new expression for the effective moment of inertia Ie first adopted in ACI CODE-318-19, this article examines the implications of this change for satisfying deflection limits of beams and one- and two-way slabs. A need is seen to revise current minimum thickness values for beams.


Document: 

CI4703Bischoff

Date: 

March 1, 2025

Author(s):

Peter H. Bischoff

Publication:

Concrete International

Volume:

47

Issue:

3

Abstract:

This is the second article in a five-part series on calculating deflections for members not meeting minimum thickness requirements in accordance with ACI CODE-318-19. It reviews the development of a new expression for the effective moment of inertia Ie used to calculate immediate deflection of cracked reinforced (nonprestressed) concrete flexural members at service load and justifies the need for a change.


Document: 

CI4702Bischoff

Date: 

February 1, 2025

Author(s):

Peter H. Bischoff

Publication:

Concrete International

Volume:

47

Issue:

2

Abstract:

The is the first article in a five-part series on calculating deflections for members not meeting minimum thickness requirements in accordance with ACI CODE-318-19. This article reviews the procedure and uncertainty for computing deflection of reinforced (nonprestressed) concrete flexural members.


Document: 

SP364_11

Date: 

December 1, 2024

Publication:

Symposium Papers

Volume:

364

Abstract:

This theoretical study discusses the serviceability of reinforced concrete beams retrofitted with near-surface-mounted (NSM) carbon fiber reinforced polymer (CFRP) strips. Particularly, the research aims to understand the tension stiffening of the strengthened beams under varying degrees of steel corrosion. Five beams are modeled and analyzed, which represent different levels of deterioration up to 100 years. The effects of tension stiffening are evaluated at service and yield loads. Results show that the tension stiffening of the beams decreases as the cross-sectional area of the steel reinforcement reduces. Likewise, the yield and ultimate capacities of the beams diminish with the reduced steel reinforcement. The effective moment of inertia formula stipulated in ACI 318-19 appears to be applicable to the NSM CFRP-retrofitted beams.

DOI:

10.14359/51745463


Document: 

SP364_01

Date: 

December 1, 2024

Author(s):

Deuckhang Lee, Hyo-Eun Joo, Sun-Jin Han, Jae Hyun Kim, and Kang Su Kim

Publication:

Symposium Papers

Volume:

364

Abstract:

In current ACI 318 code, crack control design criterion for prestressed concrete (PSC) members is stricter than conventional reinforced concrete (RC) members. In particular, it is stipulated that the net tensile stress of prestressing strands should be controlled under 250 MPa (36.3 ksi) in the serviceability design of PSC members belonging to the Class C section that is expected to be cracked under service load conditions. To this end, the nonlinear cracked section analysis is essentially required to estimate the tensile stress of the prestressing strands under the service loads, which requires cumbersome iterative calculations in practice. This study aims to propose a simplified method to estimate the net tensile stress of the prestressing strands (Δfps) under the service load conditions and also a tabulated checking method whether the net tensile stress (Δfps) exceeds the stress limit with respect to the magnitude of effective prestress (Δfse). Finally, applicability of 2,400 MPa (348 ksi) Grade strands is also experimentally investigated.

DOI:

10.14359/51745453


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