From Conceptual Design to Implementation

Over the past 15 years, and particularly following the events of September 11^th 2001, there has been increasing demand to incorporate blast resistance in important government and commercial facilities. Exterior walls of such buildings are designed to withstand blast impulse loading without a failure that would endanger building occupants, either through penetration of harmful debris or pressure waves. Operators of petrochemical facilities are also concerned about similar explosive threats due to large accidental explosions. …

Seismic design of buildings using repetitively framed CFS (CFS) members has largely been enabled through a series of dedicated tests conducted on shear walls and compiled for convenient use in the AISI-S213 standard, supported through the seismic response modification coefficients and procedures in ASCE 7. …

Cast-in-place (CIP) concrete bridge decks are typically reinforced with steel. However, poor durability resulting from steel corrosion has resulted in the use of alternative noncorrosive reinforcement materials. As part of this effort, glass fiber reinforcement polymer (GFRP) reinforcement bars have been used as structural reinforcement for CIP concrete bridge decks. GFRP is a noncorrosive composite material made of glass reinforcing fibers and a vinyl ester resin matrix. In axial tension, GFRP is elastic with brittle rupture at ultimate. Relative to grade 60 steel reinforcement, GFRP tensile strength is about 150%, the elastic modulus is about 20%, and the unit weight is about 25%. Thus, given the material’s high strength and low stiffness, serviceability of GFRP reinforced bridge decks will be an important consideration in design. …

High-strength welded wire reinforcement (WWR) mats offer a viable alternative to traditional tied rebar mats in tilt-up concrete panels. Using WWR can result in an overall decrease in reinforcing steel tonnage for the project, and allows much faster placement. Both of these factors can improve the project schedule and budget. However, there are critical differences in the panel design that must be considered. …

Cold-formed steel can be utilized in a variety of construction applications because of its versatility. This article describes two applications where one is likely to find cold-formed steel being utilized. The Cold-Formed Steel Engineers Institute (CFSEI) gave the two projects described below an Award of Merit for Design Excellence at the CFSEI EXPO in Orlando, Florida in May, 2012. …

Definitions

Porous: Possessing or full of pores, permeable to liquids.

Porosity: The ratio of the volume of interstices of a material to the volume of its mass.

Volume of Permeable Voids: Volume of space where water or air can permeate.

(From Webster’s 7^th New Collegiate Dictionary, B4C Merriam Company, 1972.) …

A Case Study

Structural Insulated Panels (SIPs) have historically been used more for residential construction than for non-residential construction. However, SIPs are gaining popularity in the commercial arena, especially for school construction. There are several schools throughout the country that have incorporated SIPs. One such school is Silvis Middle School in Silvis (East Moline), IL. …

The Advantages and Disadvantages of Lightweight Concrete in Building Construction

Recently, lightweight concrete has been implicated as the primary culprit in moisture-related failures of adhered flooring systems. Although fast-track construction techniques and government-mandated changes in flooring adhesives also have contributed to these problems, some critics suggest that the consequences of a finish floor failure outweigh the benefits that lightweight concrete can bring to a project. In light of this controversy, it is worth evaluating the advantages and disadvantages of lightweight concrete, considering not only its interactions with flooring systems but also how it affects building aspects such as steel tonnage, foundations, and slab fire ratings. Despite the moisture-related challenges that lightweight concrete poses, properly designed and constructed lightweight concrete floor slabs offer a number of efficiencies over normal-weight concrete slabs that project teams should consider. …