Practice Periodical on Structural Design and Construction

Building-focused structural engineering has been an advanced user of computational technologies over the last 3 decades. During this time, there was still a lack of integration among the participants involved in the structural design, which obstructs advancements in the structural design process. To address this, the creation of an integrated structural process model (ISPM) was formulated to promote advances in the design of structural systems through collaboration and integration among participants. The resulting ISPM is overarching in nature in that it is not specific to a structural material or system, but its scope is comprehensive because it encompasses a project from planning through construction. Within the ISPM are tasks to complete the structural processes, data-driven information exchanges among participants, and holistic representations and descriptions for methods and tools to perform the processes. The broad architectural/engineering/construction (A/E/C) impact of the structural level within the ISPM is that it prescribes an iterative manner of selecting, narrowing, and refining a system to meet the program demands and then optimizes it for efficiency and construction.

The acceptance of utilizing three-dimensional (3D) modeling programs for planning purposes in the heavy civil construction industry is on the rise. The ability to play out all possible construction process scenarios in a virtual world rather than in reality and to remove conflicts prior to the start of the work is a priceless construction planning tool. This paper explains the successful use of a 3D modeling program to plan and execute a critical lift on the Moses Wheeler Bridge project located in Connecticut. The critical lift examined here consisted of four drop-in girders. Specifically, 3D modeling was used to examine the placement of these four girders by two cranes positioned on each side of the river channel. During the planning stage, a virtual construction site was created in a commercial 3D modeling program utilizing contract plans and actual as-built survey data. Over a period of 3 days, four girder lines were erected safely and ahead of the planned project schedule. Besides the schedule gains, the project benefited from decreases in engineering costs and possible construction quality-related issues that might arise during a traditional analysis.

Placing concrete in cold weather is problematic. The contractors at the Pearl Harbor Memorial Bridge in New Haven, Connecticut, have battled relentless winters to complete the first extradosed bridge in the United States. Their success hinged on detailed winter concreting plans developed to work safely and efficiently during very cold weather. The plans contain multiple concrete mix designs as well as specific heating configurations to keep the various placement areas within acceptable temperature ranges necessary to produce quality concrete. The plans have shown to be effective, allowing placements to occur through a number of snowstorms.

The deterioration and failure of bridge deck expansion joints is an ever-growing concern among bridge researchers and designers alike. Deterioration of bridge deck expansion joints can lead to the decay of the structure beneath it, and dangerous debris can materialize in the roadway. Although repair methods vary throughout the United States, guidelines for the repair of bridge deck expansion joints do not currently exist. The purpose of this study was to provide preliminary data for the behavior of bridge deck expansion joints repaired with elastomeric concrete. The experimental study included 30 test specimens simulating the failure and repair of existing bridge deck expansion joints. The blockouts used various configurations filled with elastomeric concrete to determine the capacity of the repairs under a combination of simulated wheel and braking loads. The results showed the capacity of the repair to be more dependent on the depth of the blockouts rather than the longitudinal dimension in the direction of the roadway, while further investigation also showed a correlation with the aspect ratio of the blockouts.

Materials management is an integrated process that consists of the people, organizations, technology, and procedures used to effectively identify, quantify, acquire, expedite, inspect, transport, receive, store, and preserve the materials, equipment, and associated information across the life cycle of a capital project. The goal is to ensure that the correct quality and quantity of materials and equipment are procured in an effective manner, obtained at a reasonable cost, and available when needed. The implementation of a comprehensive materials management program contributes to more-predictable project outcomes, reduced costs, improved productivity and quality, and a safer working environment. This makes the early and comprehensive involvement of materials management in capital projects very important. This paper describes a study in which the purpose was to identify materials management techniques that reflect current and emerging practices in the capital projects industry. Surveys, interviews, and case studies involving 54 organizations were used to accomplish this purpose. The study clearly shows a dramatic increase in the maturity, formality, and systematic approach to materials management.

Smoke control is designed to enhance tenability throughout the appropriate egress time. The smoke-control system can be either a dedicated system or fully integrated with the HVAC system. In certain circumstances, the integration of the smoke-control system with the HVAC system requires additional, dedicated exhaust fans, in specific areas, for the removal of smoke. An overview of the various approaches of smoke management systems, including the four principal methods used for smoke management—passive, airflow, pressurization, and exhaust—are discussed. This paper also reviews the general aspects of the design process, as well as the various methods and approaches used in smoke-control design. Integration with the following is discussed: mechanical, electrical, and plumbing (MEP) design process; codes and regulations used for smoke control, detection, and notification; zoning; and software used for smoke-control projects. In addition, a case study has been provided as an example of the design process.

The piling framed retaining wall (PFRW) is an innovative earth-retention system applicable for soils underlain by rock, which is ideal for applications where only limited right-of-way is available or adjacent structures limit the use of tieback anchors. Two PFRWs were successfully built along the I-40/I-75 corridor in Knoxville, Tennessee, with significant cost savings over traditional retaining wall designs. Although the walls were designed using conventional earth pressure theories, the soil pressures and forces acting on the wall face are not fully understood, and a rational design method has not been fully developed. Traditional theories of lateral earth pressure assume rigid translations or rotations as the fundamental deformation mode, when in reality more complex mechanisms of deformation and earth pressure distributions may exist. A series of FEM analyses was used to evaluate the soil stresses on the face of the wall for various configurations of wall geometry, backfill slopes, and soil properties. From the results, simplified design equations were developed to predict the earth pressures on the wall face and the overturning moments for stability analyses. The proposed design equations were validated against traditional expressions and compared with earth pressures measured on the wall over a 3-year period. The measured stresses and the numerical results suggest that the typical earth pressure distribution of the PFRW is neither linear nor monotonically increasing, and the proposed design equations yield conservative results for practical combinations of geometry and soil properties. The proposed design methods offer a reliable way to predict wall pressures and overturning moments and eliminate the need to conduct extensive numerical analyses for each wall to be constructed.