# timedependent deflections of prestressed concrete beams

### Time-Dependent Deflections of Prestressed Concrete Beams

The stresses in prestressed concrete beams vary with time masmuch as the pre-stress varies. Consequently, a knowledge of the relationship between creep strain and time under constant stress is not sufficient for the analysis of time-dependent deflections of prestressed concrete beams. It is necessary to know this relationship for varying stress.

get price### Time-Dependent Deflection of Prestressed Beams by the ...

Time-Dependent Deflection of Prestressed Beams by the Pressure-Line Method Antoine E. Naaman Department of Civil Engineering, Mechanics and Metallurgy University of Illinois at Chicago Chicago, Illinois Most prestressed concrete structures are first designed and dimen-sioned on the basis of allowable stresses or strength. If a sound design

get price### Deflections of Prestressed Concrete Beams

Prestressed concrete beams undergo time-dependent deflections. The designer should be concerned with these time-dependent deflections, since they may be more than twice the initial elastic deflection. The principal cause of these deflections is creep and shrinkage of the concrete.

get price### Time-dependent prestress loss and deflection in ...

calculate time-dependent prestress loss, axial strain, curvature, and deflection of prestressed concrete members. The method, which is compared with experimental data and other established methods, covers both pretensioned and post-tensioned beams and frames. 86

get price### Time-Dependent Deformation Behavior of Prestressed High ...

research report 580-6 time-dependent deformation behavior of prestressed high performance concrete bridge beams k. a. byle, ned h. burns, and ramón l. carrasquillo center for transportation research bureau of engineering research the university of texas at austin

get price### Time-dependent assessment and deflection prediction of ...

Jun 15, 2018 A modification of the ACI 318-14 equation is proposed to calculate the long-term deflection of prestressed concrete beams with FRP or steel tendons. By introducing the prestress-related parameters η e, η p and ξ p, the proposed equation is shown to predict well the time-dependent deflection of prestressed concrete beams with unbonded CFRP ...

get price### Time-Dependent Deflections of Composite Prestressed ...

The American Concrete Institute. 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 ...

get price### Time-dependent assessment and deflection prediction of ...

This paper presents the assessment of the time-dependent behavior and the prediction of the long-term deflection of concrete beams prestressed with internal unbonded carbon fiber reinforced polymer (CFRP) tendons. A numerical model for the time-dependent analysis of concrete beams prestressed with unbonded tendons is calibrated against experimental results.

get price### INVESTIGATION OF TIME-DEPENDENT DEFLECTION IN LONG

INVESTIGATION OF TIME-DEPENDENT DEFLECTION IN LONG SPAN, HIGH STRENGTH, PRESTRESSED CONCRETE BRIDGE BEAMS Stephen D. Hinkle ABSTRACT Accurate camber prediction in prestressed concrete bridge beams is important to all parties involved in bridge design and construction. Many current prestress loss

get price### Studies of Precast/Prestressed Concrete Structures in ...

3500 days and prestressed steel-concrete composite beams for 2500 days. Theoretical formula based on age-adjusted effective modulus method and time-dependent FEM program will also be put forward to predict time-depended deflections of prestressed HPC beams and prestressed steel-concrete composite beams. Seismic behaviors of precast concrete ...

get price### Time-Dependent Deflection of Prestressed Beams by the ...

After a necessary review of available methods to estimate deflection in simply supported prestressed concrete beams, this paper proposes a new method to estimate the time-dependent deflection of prestressed beams at any time during their service life. It is called the pressure-line method because it considers the beam subjected to a compressive ...

get price### Time-dependent prestress loss and deflection in ...

calculate time-dependent prestress loss, axial strain, curvature, and deflection of prestressed concrete members. The method, which is compared with experimental data and other established methods, covers both pretensioned and post-tensioned beams and frames. 86

get price### Time-dependent prestress loss and deflection in ...

The authors propose an analytical method to calculate time-dependent prestress loss, axial strain, curvature, and deflection of prestressed concrete members. The method, which is compared with experimental data and other established methods, covers both pretensioned and posttensioned beams and frames. References. 1.

get price### Time-Dependent Deflections of Composite Prestressed ...

The American Concrete Institute. 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 ...

get price### INVESTIGATION OF TIME-DEPENDENT DEFLECTION IN

INVESTIGATION OF TIME-DEPENDENT DEFLECTION IN LONG SPAN, HIGH STRENGTH, PRESTRESSED CONCRETE BRIDGE BEAMS Stephen D. Hinkle ABSTRACT Accurate camber prediction in prestressed concrete bridge beams is important to all parties involved in bridge design and construction. Many current prestress loss

get price### [PDF] Time-dependent assessment and deflection prediction ...

Abstract This paper presents the assessment of the time-dependent behavior and the prediction of the long-term deflection of concrete beams prestressed with internal unbonded carbon fiber reinforced polymer (CFRP) tendons. A numerical model for the time-dependent analysis of concrete beams prestressed with unbonded tendons is calibrated against experimental results.

get price### Time-Dependent Deflections of Reinforced Concrete Beams ...

Jun 01, 1997 This paper proposes a method to describe the stress, strain, and deflection behavior of reinforced concrete beams. The role of compression reinforcement is included via an enhanced rational approach and an iterative technique that are designed to converge quickly, normally within two

get price### Predicting Camber, Deflection, and Prestress Losses in ...

Accurate predictions of camber and prestress losses for prestressed concrete bridge girders are essential to minimizing the frequency and cost of construction problems. The time-dependent nature of prestress losses, variable concrete properties, and problems related to production variables make it difficult to predict camber accurately.

get price### CHAPTER 13. DEFLECTION - Memphis

CIVL 4135 Deflection CHAPTER 13. DEFLECTION 13.1. Reading Assignment Text: Sect 6.4 through 6.7 and 6.9 ACI 318: Chap 9. 13.2. Calculation of Deflection of R/C beams Review of theory of deflection of homogeneous beams in elastic flexure: x y y(x) dx w(x) It is possible to make the following observations from geometry Deflection = y(x) Slope = dy/dx

get price### Long-Term Behavior of Prestressed Composite Beams at ...

Jun 06, 2008 A time-dependent analytical model is presented to predict the long-term behavior of prestressed composite beams. Close agreement is observed between the analytical and experimental results. It is proposed that the Multiplier 3.1 of the instantaneous deflection be used to calculate the deflection of prestressed composite beams for one year.

get price### TIME-DEPENDENT DEFLECTION OF PRESTRESSED AND NON ...

Download Citation On May 1, 2010, H. M. Diab and others published TIME-DEPENDENT DEFLECTION OF PRESTRESSED AND NON-PRESTRESSED FRP-STRENGTHENED STRUCTURES Find, read and cite all the research ...

get price### SP-043: Deflections of Concrete Structures

The American Concrete Institute. 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 ...

get price### Time-dependent analysis of continuous precast prestressed ...

An evaluation of the parameters affecting the time-dependent behaviour of continuous precast prestressed concrete beams has been conducted using the SSM method which was based on a finite element analysis of prestressed concrete structures using the commercially available package, ADAPT.

get price### Evaluation of Camber and Deflections for Bridge Girders

Prestressed concrete beam; steel beam; camber; deflection; rebound; creep; shrinkage; prestress loss; time-dependent behavior 18.Distribution Statement No restrictions. This document is also available to the public through the Michigan Department of Transportation. 19.Security Classif. (of this report) Unclassified 20.Security Classif. (of this ...

get price### INVESTIGATION OF TIME-DEPENDENT DEFLECTION IN

INVESTIGATION OF TIME-DEPENDENT DEFLECTION IN LONG SPAN, HIGH STRENGTH, PRESTRESSED CONCRETE BRIDGE BEAMS Stephen D. Hinkle ABSTRACT Accurate camber prediction in prestressed concrete bridge beams is important to all parties involved in bridge design and construction. Many current prestress loss

get price### [PDF] Time-dependent assessment and deflection prediction ...

Abstract This paper presents the assessment of the time-dependent behavior and the prediction of the long-term deflection of concrete beams prestressed with internal unbonded carbon fiber reinforced polymer (CFRP) tendons. A numerical model for the time-dependent analysis of concrete beams prestressed with unbonded tendons is calibrated against experimental results.

get price### Δ= 5( Pel2 )/48EI

due to prestress. In the case of sustained loads, these too are time-dependent because of concrete creep. Prediction of Deflections: Although the prediction of deflection of prestressed concrete members is complicated by such factors as the gradual reduction of prestress force due to time -dependent losses, rela tively simple procedures can be

get price### SP-043: Deflections of Concrete Structures

A Study of Post-Yielding Deflection in Simply Supported Reinforced Concrete Beams. Accurate Evaluation of Time-Dependent Deflections of Prestressed Concrete Frames. Deflection Characteristics of Structural Lightweight Reinforced and Prestressed Concrete Beams. Some Experimental Studies of Time-Dependent Deflections of Noncomposite and Composite ...

get price### Determination of Material Properties and Deflection ...

Contemporary Prestressed Beam Design, Material Properties and Deflection Behaviors Background Summary Western Transportation Institute Page 4 BACKGROUND SUMMARY Prestress concrete beams have been commonly used in bridges since the late 1950s. They have proven to be cost effective, offering good structural performance and generally requiring low

get price### Closure to “Effect of Prestressing Level on the Time ...

In conclusion, the research described in the paper is part of a larger study to investigate the time-dependent behavior of concrete beams prestressed with GFRP bars. This research mainly aimed at adding to the current work on the structural behavior of GFRP prestressed concrete beams.

get price### Theoretical Study on Short-Term and Long-Term Deflections ...

This paper presents the methods for predicting the short-term and time-dependent deflections of fully or partially prestressed concrete beams with fiber reinforced polymer (FRP) tendons under ...

get price### Evaluation of Camber and Deflections for Bridge Girders

Prestressed concrete beam; steel beam; camber; deflection; rebound; creep; shrinkage; prestress loss; time-dependent behavior 18.Distribution Statement No restrictions. This document is also available to the public through the Michigan Department of Transportation. 19.Security Classif. (of this report) Unclassified 20.Security Classif. (of this ...

get price### Long-Term Behavior of Prestressed Composite Beams at ...

Jun 06, 2008 A time-dependent analytical model is presented to predict the long-term behavior of prestressed composite beams. Close agreement is observed between the analytical and experimental results. It is proposed that the Multiplier 3.1 of the instantaneous deflection be used to calculate the deflection of prestressed composite beams for one year.

get price### CHAPTER 13. DEFLECTION - Memphis

CIVL 4135 Deflection CHAPTER 13. DEFLECTION 13.1. Reading Assignment Text: Sect 6.4 through 6.7 and 6.9 ACI 318: Chap 9. 13.2. Calculation of Deflection of R/C beams Review of theory of deflection of homogeneous beams in elastic flexure: x y y(x) dx w(x) It is possible to make the following observations from geometry Deflection = y(x) Slope = dy/dx

get price### [PDF] Prediction of time-dependent deformations in post ...

Deflection analysis is important to ensure that the reinforced or prestressed concrete flexural member will deflect within the allowable limits during its lifetime. Prediction of deflections in reinforced or prestressed concrete members can be extremely c

get price### Time-dependent analysis of continuous precast prestressed ...

An evaluation of the parameters affecting the time-dependent behaviour of continuous precast prestressed concrete beams has been conducted using the SSM method which was based on a finite element analysis of prestressed concrete structures using the commercially available package, ADAPT.

get price### ACI PRC-435-95: Control of Deflection in Concrete ...

This report presents a consolidated treatment of initial and time-dependent deflection of reinforced and prestressed concrete elements such as simple and continuous beams and one-way and two-way slab systems. It presents the state of the art in practice on deflection as well as analytical methods for computer use in deflection evaluation.

get price### Time-Dependent Finite Element Analysis of Prestressed ...

Based on ABAQUS general finite element software, UMAT Fortran subroutine is compiled to estimate the long-term deflections of prestressed concrete beams. And the calculated values using the software corresponded well with the laboratory results. By generalizing key parameters impact on long−term deflections of prestressed concrete beams, time-dependent finite element analysis was conducted.

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