Journal of Architectural Engineering

The shape of classrooms is usually rectangular with various lengths and widths. Certain parts of the classroom are better than others for viewing the board depending on the viewing distance and horizontal viewing angle. Other parts are not as good in viewing the board where students are expected to commit errors in copying from the board and may take longer time in reading. This study attempts to analyze five sections of any classroom size, and an index is developed for each section in a particular academic term to reflect cumulative hours spent in each section by students. A case study is included to apply the concepts of classroom sections. Finally, a new classroom design in the shape of a trapezoid is recommended to maximize the best area for viewing the board. Architectural engineers and architects may find it challenging to design a building with classrooms of nontraditional shape.

Current seismic design philosophies require an earthquake-resistant building capable of resisting strong motion for structures and nonstructural elements. In response to the need to understand the seismic behavior of nonstructural elements, this paper presents the study on the vibration behavior and seismic capacity of direct hung suspended (DHS) ceiling systems. Modal analysis to investigate the eigen properties of the DHS ceilings was performed. Natural frequencies and mode shapes were identified using analytical models and verified by modal experiments. Different ceiling configurations were tested to understand their ultimate strength under incremental shock spectrum excitation. It was discovered that the 45° sway wires method prescribed by Ceiling and Interior System Contractors, does not increase the seismic capacity of the entire system. Based on recent field observations of DHS ceiling earthquake damage in Taiwan, it was found that pop rivets at the molding would increase the seismic capacity of the DHS systems. It was also discovered that a constraint transverse to the excitation direction would greatly influence the behavior of a DHS system.

A laboratory test using a large-scale environmental chamber has been carried out on two flat roof models fully insulated with cellulose fiber. These two models represent the most representative single-cavity flat roofs, built in Montreal between 1930 and 1970, being insulated as part of an energy conservation program. The insulating strategy consists of packing cellulose fiber in the cavity. The goal of the test program was to determine the risk of rotting of the wood structure and moisture accumulation in the roof assembly. The test was performed using real-scale huts that were exposed to 6 months of winter and summer conditions. Two roof assemblies were each divided into five roof cavities. The main variables were the mode of moisture transfer (diffusion only and diffusion combined with air exfiltration), type of vapor barrier, and air leakage paths. The construction of the huts and the monitoring plan are described. The results of the 6-month test program using seven simulated climatic conditions are presented. Wetting and drying curves for different parts of the assemblies as well as the levels of exposure to moisture are presented and analyzed.

Experimental results of low velocity, small steel ball impact tests on laminated architectural glass units are presented. These tests are part of an ongoing effort to develop a design method for laminated architectural glass units to resist windborne debris from sources such as roof gravel, as required in several current and proposed U.S. building codes and standards. A design concept known as “sacrificial ply” permits the exterior-facing, outer glass ply of a laminated glass unit to fracture during windborne debris impacts, but prevents fracture of the inner glass ply. This concept also depends on an inner glass ply designed to resist lateral wind pressures for the remainder of the windstorm so that the integrity of the building envelope is preserved. In these experiments, inner and outer glass ply thicknesses and polyvinyl butyral interlayer thickness were varied to determine their effects on the impact resistance of the inner glass ply of laminated architectural glass when impacted on the outer glass ply. Results show that inner glass ply thickness and PVB interlayer thickness have stronger effects on the impact resistance of the inner glass ply than does outer glass ply thickness.

AISC has proposed an alternative to the use of joist girders. That proposal is based on a system that was originally developed for bridge structures. The concept was first applied to architectural structures many years ago, but was abandoned for several reasons. One principle reason for this was the system's dependence on artificial loads to balance the presence of real loads. Because of this, the system may be very susceptible to overload. The use of the Gerber System will produce a structure that is nearly half the depth of a Joist Girder System. That should be the primary reason for choosing to use the Gerber System. This paper proposes a design approach that allows this system to be used with confidence and safety. The proposed approach is based on a stiffness analysis instead of a strength analysis. The purpose of this paper is to encourage the safe use of the Gerber Framing System.