International Concrete Abstracts Portal

This paper presents a parametric analysis of the ACI 440 (2015) and AASHTO (2009) algorithms governing the flexural design of a one-way concrete member internally reinforced with glass fiber-reinforced polymer (GFRP) bars. The influence of specific design parameters on the required amount of reinforcement is investigated. The aim is to identify variables and requirements governing the design of a large-section GFRP reinforced concrete (RC) member. The member considered for this case-specific analysis is the reinforced concrete pile cap of the Halls River Bridge (Homosassa, FL), which is deemed representative of large-section GFRP-RC members operating as bent caps in short-span bridges. The influence of four critical parameters on the required amount of reinforcement is assessed. Salient analysis and design implications are discussed with respect to creep and fatigue rupture stress limits, minimum amount of flexural reinforcement, and applicable strength reduction factors. The outcomes of the parametric analysis highlight an untapped potential to reduce the required amount of reinforcement, and prioritize research areas to advance the development of rational design algorithms. Cyclic fatigue and creep rupture are identified as governing mechanisms.

The main purpose of the cement mill test report is to certify that the produced cement meets the requirements of the applicable ASTM and AASHTO cement standards. It also gives information about the average chemical and physical properties of the cement produced during a particular production period—a period that can span from a few days up to a full month. This article details what a design engineer should look for in a cement mill test report.

Recently, ASTM International and the American Association of State Highway and Transportation Officials (AASHTO) have revised their cement standards to bring them more closely in line with each other. ASTM standards are used more often in commercial construction and AASHTO standards are used more often in transportation projects; there is some overlap in the use of the different standards. The organizations undertook the harmonization effort to help promote consistency and enhance durability.

Eight years ago, when this engineer began in the welded wire industry, it was unclear what the capabilities of welded wire reinforcement were, let alone what the strength of materials and mechanical properties or testing methods were all about. Test books at that time placed WWR in a low strength and low ductility category. Until recently, WWR was a lesser extent, for structural applications. Now, with the latest technology and practices of cold-working rod to wire plus controlling speed and temperature of wire welding, the industry is producing reinforcement with much higher strengths and higher ductilities for more structural concrete applications. There has been excellent growth in this industry in recent years in structural WWR. It's being specified and used in many more building and bridge structures today. This paper deals principally with high strength steel reinforcement recognized and documented in the latest ACI 318 Structural Building Code and the latest ASTM Standards, A 82, A 185, A 496 and A 497. Reinforcing yield strength today are up to 80,000 psi (550 Mpa) Since AASHTO/LRFD and ACI specifications coincide for the most part, ACI references will be discussed. Being associated with the Wire Reinforcement Institute, this paper makes reference more to welded wire reinforcement. The paper will address code provisions related to all types of steel reinforcement in general. The name of the successful project game is to use the most readily available and most efficient reinforcing materials. There has been a considerable amount of performance research on reinforced slabs and paving done in recent years. Luke Snell of Southern Illinois University has done work on this subject. His paper, titled: "Cover of Welded Wire Fabric in Slabs and Pavements" was presented at another ACI Technical Session in Seattle, Washington on Jobsite Quality, Part 1. It implies that performance is achieved when steel reinforcement is placed and located property.