Editor’s Note

The February 2010 issue of the Practice Periodical on Structural Design and Construction contains eleven papers with focuses on bridges (three papers), roof design (one paper), construction (two papers), and design-focused methodologies for improved safety (four papers) of structures. The contributions represent works from six countries including the United States, Canada, India, Italy, China, and the Czech Republic. The issue opens with the Construction Forum and a contribution from Bernard Monahan, Editor, about construction site safety. A Technical Note regarding stiffness estimation of eccentrically braced frames is also included in this issue

The first group of papers focuses on bridges and includes a work by Dr. Giacomo Moriconi (Università Politecnica delle Marche) and Dr. Tarun R. Naik (University of Wisconsin-Milwaukee) entitled “Monitoring System to Provide Assurance for Maintenance of Structures.” This paper describes a health monitoring system for concrete structures that utilizes embedded electrodes to capture the onset of corrosion. The information collected from the sensor network is applied to a bridge management program for optimization of inspection, evaluation, and maintenance decisions. The second bridge-related paper is entitled “Planning for Commercial Vehicle Weight Limit Change: Application and Computer Software” by G. Fu (Wayne State University) et al. In this contribution, the authors present a cost-impact analysis of truck weight increase on bridge durability. The analysis considers the influence that weight has on steel fatigue, concrete deck fatigue, structural adequacy of the overall superstructure, and capacity design requirements for new bridges. The final paper in this group is a contribution from Parsons engineers Dajin Liu and Robert Magliola entitled “End Forces on Crossframes in Horizontally Curved Steel I-Girder Bridges.” The paper presents general solutions for end shear and end moments in crossframes for two- thru eight-girder systems.

The next paper in this issue is by a group of researchers from the National Research Council Canada led by Suda Molleti. The paper is entitled “Effect of Fastener-Deck Strength on the Wind Uplift Performance of Mechanically Attached Roofing Assemblies” and offers a review of a testing program that evaluated uplift performance of seven different roofing assemblies. The study identified three parameters that characterize the fasterner-deck interface strength: deck grade, deck gauge, and fastener type.

Papers on construction-related themes form the middle group of papers in this issue. The first is by Dr. George Jergeas and Dr. Janaka Ruwanpura from the University of Calgary and entitled “Why Cost and Schedule Overruns on Mega Oil Sands Projects?” The paper presents an interesting review of the efficiency of Canada’s oil sand reclamation projects, which now account for nearly half of Canada’s oil output. The second construction-related paper is by Dr. Kevin Rens and Brian Staley from the University of Colorado-Denver, and is entitled “Rating City and County of Denver Urban Pavement Constructability Using a Profiler.” The paper reviews the applicability of the International Roughness Index (IRI) to urban roadway projects. The study reviewed 23 test cases for the purpose of establishing acceptance guidelines for IRI in urban environments.

The last four papers present various design-focused methodologies that are geared toward improved structure design and safety for various structural systems. The first in this series is “Damped Properties and Noether Symmetries of Damped Free Vibration” by Jing-Li Fu (Zhejiang Sci-Tech University) et al. This paper describes the damped properties of vibration for single-degree-of-freedom systems, which can be estimated by Neother theory and then used to solve seismic analysis problems. The next paper, “New Dynamic Participation Factor (DPF) for Turbine Generator Foundations,” by Ping Gu (structural engineer), describes a new methodology to estimate the DPF from structures subject to rotational movements. This new DPF method can be used to guide selection of locations for vibration amplitude checks that will improve design of connections for large pieces of equipment. “Safety Assessment of a Steel Frame Using LRFD and SBRA Methods” by Dr. Leo Vaclavek (Technical University of Ostrava) et al. compares the safety of a steel frame structure using demand/capacity ratios calculated using simulation-based reliability assessment (SBRA) methods to the load resistance factor design (LRFD) methods. The advantages of the proposed SBRA over LRFD are described.

The last paper in the design-focused series is “Improved Design of Embedment Depths for Transmission Pole Foundations Subject to Lateral Loading,” by Dr. Sivapalan Gajan (North Dakota State University) and Ms. Cassie McNames (Ulteig Engineers). The paper describes a review of design methods for pole foundations that utilizes refined lateral load analysis procedures that account for variable soil conditions, pole stiffness, etc. The revised methods are shown through case studies to improve the design embedment depth.

A case study paper that reviews the comparative analysis of differential settlements on a boiler structure foundation makes up the last paper in this compendium. The paper, “Interplanar and Intraplanar Differential Settlement Analysis of Boiler Supporting Structure—Comparative Study,” by Suneel Kumar (S.V. University, India) and P. Jayabalan (National Institute of Technology, India) discusses the effects of soil properties and load combinations on differential settlement of a boiler structure at a thermal power plant.

While the papers presented in this issue cover a wide range of topics and structures, they all contribute useful and timely information that can be readily put into practice.

The editorial board thanks the authors of this issue’s papers, and encourages readers to submit discussion and comment on the subject matter presented. Discussions and comments should be submitted as stipulated in the General Information section, which can be found at the front of the Journal.