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Shear capacity of reinforced concrete beams using neural networkYang, Keun-Hyeok, Ashour, Ashraf, Song, J-K. January 2007 (has links)
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.
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Stability of Castellated Beams During ErectionBradley, T. Patrick 05 February 2003 (has links)
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
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Feasibility of open web rafters constructed of single anglesHagenBurger, William C. 14 April 2009 (has links)
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
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Influence of section depth on the structural behaviour of reinforced concrete continuous deep beamsYang, Keun-Hyeok, Ashour, Ashraf January 2007 (has links)
Yes / Although the depth of reinforced concrete deep beams is much higher than that of slender beams, extensive existing
tests on deep beams have focused on simply supported beams with a scaled depth below 600 mm. In the present
paper, test results of 12 two-span reinforced concrete deep beams are reported. The main parameters investigated
were the beam depth, which is varied from 400 mm to 720 mm, concrete compressive strength and shear span-tooverall
depth ratio. All beams had the same longitudinal top and bottom reinforcement and no web reinforcement to
assess the effect of changing the beam depth on the shear strength of such beams. All beams tested failed owing to
a significant diagonal crack connecting the edges of the load and intermediate support plates. The influence of
beam depth on shear strength was more pronounced on continuous deep beams than simple ones and on beams
having higher concrete compressive strength. A numerical technique based on the upper bound analysis of the
plasticity theory was developed to assess the load capacity of continuous deep beams. The influence of the beam
depth was covered by the effectiveness factor of concrete in compression to cater for size effect. Comparisons
between the total capacity from the proposed technique and that experimentally measured in the current investigation
and elsewhere show good agreement, even though the section depth of beams is varied.
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The aperture averaged scintillation of the intensity of a Gauss ian laser beam propagated through strong optical turbulance and reflected by various targetsAl Habash, M. Ammar 01 July 2000 (has links)
No description available.
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Crack growth measurement and fracture toughness of plain concrete beamsJones, Gary Lee January 2011 (has links)
Includes photographs. / Digitized by Kansas Correctional Industries
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Fracture toughness testing of small concrete beamsRood, Sheryl. January 1984 (has links)
Call number: LD2668 .T4 1984 R66 / Master of Science
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Ultraprecise nanofabrication with extremely low dose focused ion beamsHabibi, Sina January 2014 (has links)
No description available.
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Effects of repeated loading on prestressed concrete composite beams鍾大元, Chung, Tai-yuen, Eric. January 1974 (has links)
published_or_final_version / Civil Engineering / Master / Master of Philosophy
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Seismic design recommendations for high-strength concrete beam-to-column connections.Alameddine, Fadel F. January 1990 (has links)
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.
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