Thesis (M.S.)--University of Alabama at Birmingham, 2008. / Additional advisors: James Davidson, Jason Kirby, Talat Salama. Description based on contents viewed Feb. 11, 2009; title from PDF t.p. Includes bibliographical references (p. 97-99).

Thesis (Ph. D.)--Lehigh University, 2006. / Includes vita. Includes bibliographical references (leaves 360-363).

The purpose of the research reported here was to determine if single angles can be used for chord and web members in lightweight steel open web rafters, and if so to determine what effect the single angles have on the design of the rafter's members. A computer model was constructed to determine the effects of a unsymetric cross section coupled with eccentric loadings of the members on out-or-plane displacements, and bending moments and stresses in the chord and web members. This computer model modeled the eccentricities and unsymetric section properties of the single angles. A study of the effect of out-or-plane bracing on the bending moments and stresses was also conducted. Finally various web configurations (angle web members on the same side, alternating, and opposite) were studied to determine their effect on moments in the web and chord members, along with their effect on out-or-plane displacements. A preliminary design procedure for chord and web members using the new AISC ""Specification For Allowable Stress Design of Single Angle Members" is presented. Finally suggestions on out-of-plane bracing and connections are made. / Master of Science

No description available.

Thesis (Ph. D.)--University of Alabama at Birmingham, 2008. / Title from PDF title page (viewed Jan. 28, 2010). Additional advisors: Michael Anderson, Fouad Fouad, Wilbur Hitchcock, Virginia Sisiopiku. Includes bibliographical references (p. 203-208).

Experiments were performed to examine the shear resistance of heavily reinforced I-beams. Six I-beams with identical cross sections were constructed using high strength self-consolidating concrete, and were tested under monotonic anti-symmetric loading. All specimens had almost the same amount of longitudinal reinforcement, which provided sufficient flexural capacities. There were two variables: shear span and shear reinforcement ratio. Test results showed that ACI code was too conservative in predicting the shear strengths of heavily shear reinforced I-beams, and the shear strength limit for deep beams should be increased to account for the benefit of high strength concrete. However, doubling the amount of stirrups did not improve the ultimate shear resistance much. The three beams that contained around 2.45% stirrups showed over-reinforced shear failures. Longitudinal flange cracking occurred to every specimen due to lack of cross tie reinforcement in the flanges, and it was believed to have reduced the ultimate shear strength.

Experiments were performed to examine the shear resistance of heavily reinforced I-beams. Six I-beams with identical cross sections were constructed using high strength self-consolidating concrete, and were tested under monotonic anti-symmetric loading. All specimens had almost the same amount of longitudinal reinforcement, which provided sufficient flexural capacities. There were two variables: shear span and shear reinforcement ratio. Test results showed that ACI code was too conservative in predicting the shear strengths of heavily shear reinforced I-beams, and the shear strength limit for deep beams should be increased to account for the benefit of high strength concrete. However, doubling the amount of stirrups did not improve the ultimate shear resistance much. The three beams that contained around 2.45% stirrups showed over-reinforced shear failures. Longitudinal flange cracking occurred to every specimen due to lack of cross tie reinforcement in the flanges, and it was believed to have reduced the ultimate shear strength.

When taking steps away from tried and true designs, there is always a degree of uncertainty that arises. With the introduction of fiber-reinforced polymers (FRP) in double-web I-beams (DWIB) to replace steel beams in bridge applications, there are many benefits along with the disadvantages. A bridge has been built with this new type of beam after only short-term proof testing for validation. Nondestructive evaluation (NDE) is a way to implement health monitoring of the bridge beams and needs to be assessed. The principal underlying infrared thermal imaging (IR) nondestructive evaluation (NDE) is to induce a thermal gradient in the beam through heating and monitor how it changes. Delaminations determined by others to be the critical form of deterioration, would be expected to affect the heat conduction in these beams. This project used a halogen lamp to heat the surface of the beam followed by an observation with an IR camera. Calculations of an ANSYS finite element analysis (FEA) model were compared with a series of laboratory tests. The experimental results allowed for validation of the model and development of an IR inspection procedure. This work suggests that for high quality beams of the type considered that an IR procedure could be developed to detect delaminations as small as one inch in length; however, the size would be underestimated. / Master of Science

The construction of horizontally curved bridges with skewed supports requires careful consideration. These types of bridges exhibit three-dimensional response characteristics that are not commonly seen in straight bridges with normal supports. As a result, engineers may face difficulties during the construction, when the components of the bridge do not fit together or the final geometry of the structure does not correspond to that intended by the designer. These complications can lead to problems that compromise the serviceability aspects of the bridge and in some cases, its structural integrity. The three dimensional response that curved and skewed bridges exhibit is directly influenced by the bracing system used to configure the structure. In I-girder bridges, cross-frames are provided to integrate the structure, transforming the individual girders into a structural system that can support larger loads than when the girders work separately. In general, they facilitate the construction of the structure. However, they can also induce undesired collateral effects that can be a detriment to the performance of the system. These effects must be considered in the design of a curved and skewed bridge because, in some cases, they can modify substantially its response. This research is focused on understanding how the bracing system affects the performance of curved and skewed I-girder bridges, as well as, the ability of the approximate analysis methods to capture the structural behavior. In this research, techniques that can be implemented in the creation of 2D-grid models are developed to overcome the limitations of this analysis method. In addition, efficient cross-frame arrangements that mitigate the collateral effects of skew are developed. These mitigation schemes reduce the undesired cross-frame forces and flange lateral bending stresses associated with the transverse stiffness of the structure, while ensuring that the bracing system still performs its intended functions.

Изучена эффективность применения и рациональность использования гофрированных конструкций для проектирования сейсмостойких стальных рамных каркасов с использованием современных методов сейсмозащиты. / Studied the effectiveness of the use and rationality of the use corrugated structures for the design of earthquake-resistant steel frames using modern methods of seismic protection.