no / Composite beams formed by connecting the concrete slabs to the supporting steel beams have been in use for many years. Much of the research into this form of construction has concentrated on the more traditional reinforced concrete and metal deck construction. In composite beam design, the strength of the shear connector is of great importance since longitudinal shear forces must be transferred across the steel-concrete interface by the mechanical action of shear connectors. The shear strength and stiffness of the connection is not only dependent on the strength of the connector itself, but also on the resistance of the concrete slab to longitudinal cracking caused by the high concentration of shear force at each connector. Present knowledge of this behaviour is limited to shear connectors in solid reinforced concrete slabs and concrete slabs with profiled sheeting, little information is given for the shear connector capacity on composite steel beam with precast hollow core slabs. A new horizontal push off test is proposed to determine the shear capacity of the connector on the composite beams with precast concrete hollow cored floor slabs. The results showed the new test is compatible with all type of floor and shear connectors, and can replace the existing vertical push off tests.

No / Optimum multi-layered feed-forward neural network (NN) models using a resilient back-propagation algorithm and early stopping technique are built to predict the shear capacity of reinforced concrete deep and slender beams. The input layer neurons represent geometrical and material properties of reinforced concrete beams and the output layer produces the beam shear capacity. Training, validation and testing of the developed neural network have been achieved using 50%, 25%, and 25%, respectively, of a comprehensive database compiled from 631 deep and 549 slender beam specimens. The predictions obtained from the developed neural network models are in much better agreement with test results than those determined from shear provisions of different codes, such as KBCS, ACI 318-05, and EC2. The mean and standard deviation of the ratio between predicted using the neural network models and measured shear capacities are 1.02 and 0.18, respectively, for deep beams, and 1.04 and 0.17, respectively, for slender beams. In addition, the influence of different parameters on the shear capacity of reinforced concrete beams predicted by the developed neural network shows consistent agreement with those experimentally observed.

The increased depth of castellated beams presents stability problems, specifically during erection. During erection the castellated beam must support the weight of an erector and self-weight until the continuous bracing of the floor deck is in place. The stability of the unbraced member is based on its resistance to lateral-torsional buckling. The cross-sectional properties that are related to lateral-torsional buckling, such as out-of-plane bending, warping constant, and torsional constant were calculated using three different approaches to model the unique geometry of castellated beams. These properties were used in various lateral-torsional buckling solutions to determine which procedure should be used to check for this mode of failure. Two specimens were tested to evaluate the results of the analytical unbraced length determination process. The tests results were used to better model the contribution of the web-to-column flange double angle connection on the stability of the castellated beam. / Master of Science

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.

Includes photographs. / Digitized by Kansas Correctional Industries

Call number: LD2668 .T4 1984 R66 / Master of Science

No description available.

published_or_final_version / Civil Engineering / Master / Master of Philosophy

The present recommendations of the ACI-ASCE Committee 352 for the design of ductile moment resistant beam to column connections limit the joint shear stress to γ√f'(c), where the factor γ is a function of the joint geometric classification and the loading condition. The value of compressive strength f'(c) used in the above expression should not exceed 6000 psi. This limitation causes considerable difficulty in the design of high-strength concrete frames. An experimental study of twelve large-scale exterior beam to column subassemblies was completed at The University of Arizona. The specimens were subjected to cyclic inelastic loading. The variables studied were the concrete compressive strength (8.1, 10.7, and 13.6 ksi), the joint shear stress (1100 and 1400 psi), and the degree of joint confinement provided in the form of closed ties. Although high-strength concrete is more brittle than normal-strength concrete, the study showed that frames constructed of high-strength concrete can perform satisfactorily in earthquakes zones when attention is given to proper detailing of joints. The flexural strength ratio, degree of joint confinement, development length of bars, and joint shear stress are all very important factors to be considered in the design process. The maximum permissible joint shear stress suggested by ACI-ASCE Committee 352 was modified for frames constructed with high-strength concrete. The proposed joint shear stress drawn from test results does not affect the factor γ which depends on the joint type and its geometric classification. Therefore, in the absence of any further data about interior joints, the proposed joint shear limit for high-strength concrete can be used for all types and geometric classifications of joints. Furthermore, new requirements for joint confinement were presented to ensure ductile behavior of frames. It is important to note that current Recommendations for joint confinement, which were developed for normal-strength concrete, cannot be satisfied for high-strength concrete frames. The hysteresis response of specimens tested and other normal-strength concrete specimens tested by different investigators were compared in terms of their energy absorption capacity. This comparison was essential to alleviate concern about the lack of ductility of high-strength concrete. Favorable results were obtained. This research is important for practitioners to gain more confidence using high-strength concrete for structural design applications especially in seismic zones.