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.

Performance of Precast Concrete Building Structures

2012 ◽  
Vol 28 (1_suppl1) ◽  
pp. 349-384 ◽  
Author(s):  
S. K. Ghosh ◽  
Ned M. Cleland
Keyword(s):  
Prestressed Concrete ◽  
Precast Concrete ◽  
Lateral Force ◽  
Building Code ◽  
Earthquake Resistance ◽  
Building Structures ◽  
Building Systems ◽  
Concrete Building ◽  
Precast Prestressed Concrete ◽  
Code Provisions

The Precast/Prestressed Concrete Institute (PCI) sent an assessment team to Chile, which visited the areas affected by the 27 February 2010 earthquake between 26 and 30 April 2010. This paper reports on the team's observations on the performance of precast/prestressed concrete structures. The precast concrete building systems observed by the PCI team generally performed well. In some cases, the lateral force-resisting system performed satisfactorily, but the absence or weakness of diaphragm framing resulted in local failures. Overall, the PCI team found a mature and sophisticated precast concrete industry that has successfully considered and solved issues of earthquake resistance without some of the constraints imposed on U.S. practice by restrictive building code provisions.

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.

Structural integrity of precast concrete modular construction

PCI Journal ◽  
2021 ◽  
Vol 66 (2) ◽  
pp. 58-70
Author(s):  
Jeff M. Wenke ◽  
Charles W. Dolan
Keyword(s):  
Prestressed Concrete ◽  
Structural Integrity ◽  
Precast Concrete ◽  
Building Code ◽  
Modular Construction ◽  
Structural Concrete ◽  
Partial Removal ◽  
Structural Walls ◽  
Construction Methods ◽  
General Services Administration

The American Concrete Institute’s (ACI’s) Building Code Requirements for Structural Concrete (ACI 318-19) and Commentary (ACI 318R-19) contains structural integrity provisions for precast concrete panel buildings but does not address the structural integrity of precast concrete modules. ACI 318 requires spaced steel ties in all directions to tie the precast concrete panel elements together. These criteria are impractical for precast concrete modules due to the construction methods and the overall rigidity of each module. Precast concrete modules are inherently stable, even when subjected to General Services Administration criteria for partial removal of structural walls or corners, which require that if a portion of a wall or an entire module is removed, the remaining portions must have sufficient capacity to carry the resulting gravity loads. This paper examines the stress increases due to partial wall removal and the possibility of total module removal. It discusses strength reserves, provides recommendations for future editions of ACI 318 and the PCI Design Handbook: Precast and Prestressed Concrete, and presents conceptual connections that provide the continuity and ductility needed to maintain structural integrity following total module removal.

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 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.

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.

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.

scholarly journals Precast Prestressed Concrete Truss-Girder for Roof Applications

2014 ◽  
Vol 2014 ◽  
pp. 1-13 ◽  
Author(s):  
Peter Samir ◽  
George Morcous
Keyword(s):  
Cross Sections ◽  
Prestressed Concrete ◽  
Precast Concrete ◽  
Maintenance Cost ◽  
Element Analysis ◽  
Long Span ◽  
Structural Capacity ◽  
Bridge Girder ◽  
Steel Trusses ◽  
Precast Prestressed Concrete

Steel trusses are the most popular system for supporting long-span roofs in commercial buildings, such as warehouses and aircraft hangars. There are several advantages of steel trusses, such as lightweight, ease of handling and erection, and geometric flexibility. However, they have some drawbacks, such as high material and maintenance cost, and low fire resistance. In this paper, a precast concrete truss is proposed as an alternative to steel trusses for spans up to 48 m (160 ft) without intermediate supports. The proposed design is easy to produce and has lower construction and maintenance costs than steel trusses. The truss consists of two segments that are formed using standard bridge girder forms with block-outs in the web which result in having diagonals and vertical members and reduces girder weight. The two segments are then connected using a wet joint and post-tensioned longitudinally to form a crowned truss. The proposed design optimizes the truss-girder member locations, cross-sections, and material use. A 9 m (30 ft) long truss specimen is constructed using self-consolidated concrete to investigate the constructability and structural capacity of the proposed design. A finite element analysis of the specimen is conducted to investigate stresses at truss diagonals, verticals, and connections. Testing results indicate the production and structural efficiency of the developed system.

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