scholarly journals Structural Health Monitoring of Precast Concrete Box Girders Using Selected Vibration-Based Damage Detection Methods

2010 ◽  
Vol 2010 ◽  
pp. 1-21 ◽  
Author(s):  
Zhengjie Zhou ◽  
Leon D. Wegner ◽  
Bruce F. Sparling
Keyword(s):  
Damage Detection ◽  
Prestressed Concrete ◽  
Precast Concrete ◽  
Detection Methods ◽  
Box Girders ◽  
Localization Accuracy ◽  
Structural Health ◽  
Proportional Increase ◽  
Low Levels ◽  
Precast Prestressed Concrete

Precast, prestressed concrete box girders are commonly used as superstructure components for short and medium span bridges. Their configuration and typical side-by-side placement make large portions of these elements inaccessible for visual inspection or the application of nondestructive testing techniques. This paper demonstrates that vibration-based damage detection (VBDD) is an effective alternative for monitoring their structural health. A box girder removed from a dismantled bridge was used to evaluate the ability of five different VBDD algorithms to detect and localize low levels of spalling damage, with a focus on using a small number of sensors and only the fundamental mode of vibration. All methods were capable of detecting and localizing damage to a region within approximately 1.6 times the longitudinal spacing between as few as six uniformly distributed accelerometers. Strain gauges configured to measure curvature were also effective, but tended to be susceptible to large errors in near support damage cases. Finite element analyses demonstrated that increasing the number of sensor locations leads to a proportional increase in localization accuracy, while the use of additional modes provides little advantage and can sometimes lead to a deterioration in the performance of the VBDD techniques.

PCI Standard Design Practice Ref ACI 318-14

2021 ◽  
Author(s):  
Keyword(s):  
Prestressed Concrete ◽  
Precast Concrete ◽  
Building Code ◽  
Design Practice ◽  
Structural Concrete ◽  
Design Engineers ◽  
Standard Design ◽  
Precast Prestressed Concrete ◽  
Consistent Approach ◽  
Code Provisions

Precast, prestressed concrete design is based on conformance with the provisions of the American Concrete Institute’s (ACI’s) Building Code Requirements for Structural Concrete (ACI 318-14) and Commentary (ACI 318R-14). In most cases, these provisions are followed explicitly. Occasionally, interpretation of some sections of ACI 318 is required to ensure quality is maintained in conjunction with the unique characteristics of precast and prestressed concrete fabrication, shipping, and erection. Members of the PCI Building Code Committee, along with other experienced precast concrete design engineers, have identified code provisions, detailed in this publication, that require clarification or interpretation. These design practices are followed by most precast concrete design engineers to produce safe, economical precast concrete structures and they provide a consistent approach for the designers and contractors.

scholarly journals Experimental Study of a New Precast Prestressed Concrete Joint

2018 ◽  
Vol 8 (10) ◽  
pp. 1871 ◽  
Author(s):  
Xueyuan Yan ◽  
Suguo Wang ◽  
Canling Huang ◽  
Ai Qi ◽  
Chao Hong
Keyword(s):  
Energy Dissipation ◽  
Seismic Performance ◽  
Prestressed Concrete ◽  
Precast Concrete ◽  
Concrete Strength ◽  
Frame Structure ◽  
Loading Test ◽  
Concrete Frame ◽  
Concrete Joints ◽  
Precast Prestressed Concrete

Precast monolithic structures are increasingly applied in construction. Such a structure has a performance somewhere between that of a pure precast structure and that of a cast-in-place structure. A precast concrete frame structure is one of the most common prefabricated structural systems. The post-pouring joint is important for controlling the seismic performance of the entire precast monolithic frame structure. This paper investigated the joints of a precast prestressed concrete frame structure. A reversed cyclic loading test was carried out on two precast prestressed concrete beam–column joints that were fabricated with two different concrete strengths in the keyway area. This testing was also performed on a cast-in-place reinforced concrete joint for comparison. The phenomena such as joint crack development, yielding, and ultimate damage were observed, and the seismic performance of the proposed precast prestressed concrete joint was determined. The results showed that the precast prestressed concrete joint and the cast-in-place joint had a similar failure mode. The stiffness, bearing capacity, ductility, and energy dissipation were comparable. The hysteresis curves were full and showed that the joints had good energy dissipation. The presence of prestressing tendons limited the development of cracks in the precast beams. The concrete strength of the keyway area had little effect on the seismic performance of the precast prestressed concrete joints. The precast prestressed concrete joints had a seismic performance that was comparable to the equivalent monolithic system.

scholarly journals Influence of end Contsrains on the Global Behaviour of a Box Girder

2016 ◽  
Vol 6 (1) ◽  
pp. 7-15
Author(s):  
Daniela Mihaela Boca ◽  
A. Faur ◽  
A. Boca
Keyword(s):  
Prestressed Concrete ◽  
Transport Infrastructure ◽  
Box Girders ◽  
3D Fem ◽  
Important Data ◽  
Box Girder ◽  
Fem Model ◽  
Global Behaviour ◽  
Applied Forces ◽  
Precast Prestressed Concrete

Abstract This study aims to presents the importance of end constrains, boundary conditions and position of the applied forces regarding the design of precast/prestressed concrete box girders. The study is based on a destructive test which was performed on a 37.1 m span single-cell prestressed concrete box girder. The scope of the test was to certify the usage of such girders for the new Transylvania motorway bridges. The test is numerically reproduced through a full 3D FEM model implemented in SAP2000. The influence of the end diaphragms is considered by analysing the beam’s behaviour to six loading conditions: one of which is replicating the loadings during the test, while the others are conceived as real vertical and horizontally loading scenarios. The results obtained for the girders with and without end constrains are compared. The performances of both design solutions in the presence of prestressing are highlighted where applicable. It is considered that the results of this study may provide very important data if considering that Romania has an urgent need to realize a modern and an adequate transport infrastructure.

Saint-Venant torsion constant of modern precast concrete bridge girders

PCI Journal ◽  
2021 ◽  
Vol 66 (3) ◽  
pp. 23-31
Author(s):  
Richard Brice ◽  
Richard Pickings
Keyword(s):  
Prestressed Concrete ◽  
High Performance Concrete ◽  
Precast Concrete ◽  
The United States ◽  
Bridge Girders ◽  
Concrete Bridge ◽  
Approximate Methods ◽  
Standard Design ◽  
Prestressed Concrete Bridge ◽  
Precast Prestressed Concrete

Many bridge owners have developed new precast, prestressed concrete bridge girder sections that are optimized for high-performance concrete and pretensioning strands with diameters greater than 0.5 in. (12.7 mm). Girder sections have been developed for increased span capacities, while others fill a need in shorter span ranges. Accurate geometric properties are essential for design. Common properties, including cross-sectional area, location of centroid, and major axis moment of inertia, are generally easy to compute and are readily available in standard design references. Computation of the torsion constant is a different matter. This paper presents the methods and results of a study to determine the torsion constant for many of the modern precast, prestressed concrete bridge girders used in the United States and compares the results with values from the approximate methods of the AASHTO LRFD specifications.

Genetic Analysis and Repair of Cracks in Prestressed Concrete Box Girders during Precast Period

2011 ◽  
Vol 366 ◽  
pp. 55-58
Author(s):  
Shi Ming Liu ◽  
Shun Bo Zhao
Keyword(s):  
Genetic Analysis ◽  
Prestressed Concrete ◽  
Initial Period ◽  
Environmental Condition ◽  
Box Girders ◽  
Construction Procedure ◽  
Precast Prestressed Concrete ◽  
Space Width ◽  
Construction Works

During the initial period of precast prestressed concrete box girders in a bridge, some cracks appeared in five box girders. The paper describes the crack states including location, elongation, space, width and depth. The geneses of the cracks are analyzed considering the concrete proportion, environmental condition and construction procedure. Four of them were permitted to be used after mending of these cracks and another one was abandoned directly. After the preventing measurement was adopted, no cracks appeared in the follow-up precast box girders. The experience can be as reference for the similar construction works.

scholarly journals Load Distribution In Adjacent Precast "Deck Free" Concrete Box-Girder Bridges

2021 ◽  
Author(s):  
Waqar Khan
Keyword(s):  
Prestressed Concrete ◽  
Precast Concrete ◽  
Box Girders ◽  
Box Girder Bridges ◽  
Box Girder ◽  
Girder Bridges ◽  
Concrete Box Girder ◽  
Concrete Box Girder Bridges ◽  
Girder Bridge ◽  
The Moment

Bridges built with adjacent precast, prestressed concrete box-girders are a popular and economical solution for short-span bridges because they can be constructed rapidly. The top flanges of the precast box girders form the bridge deck surface. A shear key is introduced between the adjacent boxes over the depth of the top flange (i.e. 225 mm thick as the thickness of the box's top flange). Canadian Highway Bridge Design Code, CHBDC specifies empirical equations for the moment and shear distribution factors for selected bridge configurations but not for adjacent precast concrete box-girder bridge type. In this study, a parametric study was conducted, using the 3D finite-element modeling, and a set of simplified equations for the moment, shear and deflection distribution factors for the studied bridge configuration was developed.

Precast Prestressed Concrete Pavement Pilot Project near Georgetown, Texas

2003 ◽  
Vol 1823 (1) ◽  
pp. 11-17 ◽  
Author(s):  
David K. Merritt ◽  
B. Frank McCullough ◽  
Ned H. Burns
Keyword(s):  
Prestressed Concrete ◽  
Precast Concrete ◽  
Pilot Project ◽  
The United States ◽  
Concrete Pavements ◽  
Portland Cement Concrete ◽  
Pavement Construction ◽  
Under Construction ◽  
Transportation Research ◽  
Precast Prestressed Concrete

The use of precast concrete is rapidly becoming a viable method for repair and rehabilitation of portland cement concrete pavements, with several projects under construction or in development throughout the United States. Construction with precast concrete offers numerous benefits over conventional cast-in-place pavement construction. Most notable is how quickly a precast pavement can be opened to traffic. Precast panels can be placed during overnight or weekend operations and opened to traffic almost immediately. In addition, because precast panels are cast in a controlled environment, the durability of a precast pavement is also improved. In March 2002, the Texas Department of Transportation completed construction of a precast pavement pilot project aimed at testing and further developing a precast pavement concept developed by the Center for Transportation Research at The University of Texas at Austin. This project was constructed on a section of frontage road along Interstate 35 near Georgetown, Texas. The project incorporated the use of posttensioned precast concrete panels. The panels were posttensioned in place not only to tie all the panels together but also to reduce the pavement thickness required and improve durability. The finished pavement demonstrated not only the viability of precast pavement construction but also the benefits of incorporation of posttensioning. Although the project was constructed without the time constraints and complexities that will eventually need to be considered for precast pavement construction, it ultimately helped to develop viable construction procedures for future precast prestressed concrete pavements.

Damage Detection for SMC Benchmark Problem: A Subspace-Based Approach

2016 ◽  
Vol 16 (04) ◽  
pp. 1640025 ◽  
Author(s):  
Wensong Zhou ◽  
Shunlong Li ◽  
Hui Li
Keyword(s):  
Structural Health Monitoring ◽  
Damage Detection ◽  
Health Monitoring ◽  
Full Scale ◽  
Detection Methods ◽  
Benchmark Problems ◽  
Small Scale ◽  
Benchmark Problem ◽  
Monitoring And Control ◽  
Structural Health

A full-scale bridge benchmark problem was issued by the Center of Structural Monitoring and Control at the Harbin Institute of Technology. The data used in this problem were collected by an in situ structural health monitoring system implemented into a full-scale cable-stayed bridge before and after the bridge was damaged, which is very rare in structural health monitoring field. This benchmark problem will help to verify and/or make comparison of the condition assessment and the damage detection methods, which are usually validated by numerical simulation and/or laboratory testing of small-scale structures with assumed deterioration models and artificial damage. With respect to damage detection of girder, one of the benchmark problems, using the monitored and field testing acceleration data, this paper describes a damage detection method, based on a residual generated from a subspace-based covariance-driven identification method, to detect the damage, and give relative quantitative damage indexes. This method was applied on both two parts of the given benchmark problem, and then detailed discussions and results on this problem are reported in this paper.

Load-Deflection Analysis of Pretensioned Inverted T-Beam with Web Openings

2008 ◽  
Vol 400-402 ◽  
pp. 865-872 ◽  
Author(s):  
Hock Tian Cheng ◽  
S. Mohammed Bashar ◽  
Kamal Nasharuddin Mustapha
Keyword(s):  
Analytical Solution ◽  
Prestressed Concrete ◽  
Precast Concrete ◽  
Experimental Program ◽  
Web Openings ◽  
Deflection Analysis ◽  
Experimental Values ◽  
Simplified Procedure ◽  
T Beam ◽  
Precast Prestressed Concrete

A precast, prestressed concrete girder with circular web openings allows building service systems (mechanical, electrical, communications, and plumbing) to cross the girder line within the member’s depth, reducing a building’s floor-to-floor height and the overall height of the structure. These height reductions have the potential to improve the competitiveness of total precast concrete structures versus other types of building systems. The experimental program reported in this paper tested five full-scale inverted-tee girders with circular web openings to failure, to evaluate the openings’ effect on girder behavior. The girders failed in a ductile manner due to diagonal cracking above the openings. The tested girders were designed using available recommendations in the existing literatures. It was observed that concrete fractured from tension zones around an opening, with cracks developing vetically towards the beam flanges. A beam would collapse when the cracks reached the flanges. In the present work, an analytical solution is developed for the load-deflection calculation of prestressed beam with web openings at any load stage. The solution assumes a trilinear deflection response characterized by the flexural cracking initiation, steel yielding, and ultimate capacity. Closed form expressions are presented for the case of simple beams subjected to four-points loading. These expressions are modified from present ACI code equations by incorporating appropriate laboratory determined coefficients in order to predict more precisely with some degree of conservativeness on flexural load-point deflection with any extent of uncracked, postcracked, and postyielded region along their spans. Accordingly, a simplified analysis procedure is developed by adopting a trilinear load-deflection response. The effectiveness of the simplified procedure is demonstrated by comparing its results to those of the analytical solution and the experimental values.

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