Abstract: Single span highway bridges of composite construction are idealized as beams as well as an orthotropic plate. A standard HS-20-44 highway vehicle is represented by a planar, two axle, sprung mass system with a frictional device. The response equations are derived in terms of the natural modal coordinates of the bridge and of displacement coordinates of the vehicle. The bridge dynamic loadings due to the initial bounce of the vehicle and in combination with the braking of the vehicle are investigated for symmetric as well as eccentric loading of the vehicle.

Abstract: The spans of a random walk on a simple cubic lattice are the sides of the smallest rectangular box with sides parallel to the coordinate axes that entirely contain the random walk. We consider the position, at dimension-less time τ, of a random walker constrained by a set of spansS. We show in one dimension that ifS 2 ≫ 4τ, the random walker tends to be located at the extremities of the span, while in the contrary case the random walker is most likely to be found halfway between the extremities. This is true whether the single-step transition probabilities have a finite or an infinite variance, as is shown by example. In higher dimensions the position of the random walker in the direction of the largest span tends to lie at the span extremities, while the position in the direction of the smallest span tends to be in the middle.

Abstract: Transonic modified small-disturbance theory has been employed to numerically model the flowfield around wing/fuselage/pylon/store configurations. A fine grid region enclosing the wing/pylon/store is embedded within a global crude grid and a successive crude-fine relaxation is performed. Using an image point concept, the store and the pylon are introduced into an existing wing/fuselage program, thus avoiding excessive additional computer memory requirements. Comparison of results with experiments on the F-5 wing with a pylon/store arrangement is presented showing good agreement. A study of the roles of pylon height, store diameter, pylon span mount location, angle of attack, and Mach number relative to the achievement of optimum LID from beneficial nonlinear interference is presented. In addition, a simplified analytical approach to compute the loading on the store using an "immersion theory" is indicated and validated against experiments.

Abstract: Full span form panel bridges are bridges constructed of prestressed precast panels spanning from pier to pier and covered with a composite topping concrete. This research concerns such full span bridges. Research consists of field investigations, including corings, analytical modeling, laboratory testing, and field testing. Results demonstrate safety of bridges designed using A.A.S.H.T.O. effective width formula and describe details thought to be capable of reducing cracking observed in existing full span form panel bridges. (Author)

Abstract: Nondimensional dynamic responses of simple and multiply-supported, horizontally curved beams with moving loads are measured in laboratory-scale experiments. Effects of system parameters involving span stiffness, arc length, frequency, end support constraints, and various transit load speeds and spacings are investigated. For critical combinations of certain parameters, adverse coupling of bending and torsional span responses are observed. For instance, as critical load speeds are approached, measured twist angles and bending strains at midspan approach unboundedness for multiple spans, but are bounded for equivalent simple spans placed end-to-end. Calculations based on Bernoulli-Euler curved beam theory (with negligible warping rigidity) complement these simple span measurements. Experiments also include multiple spans with up to 90? turns, subject to both transit point loads in tandem and sprung vehicles. Results are applicable to dynamic span designs for mass transit systems.

Abstract: This article discusses the collection and analysis of field data on bridge movements and the ability of bridges to tolerate these movements. It was concluded that many bridges, depending upon kind of span, length of span, and kind of construction material, can tolerate significant levels of differential settlement without sustaining intolerable structural damage. However, the horizontal movement of substructure elements was found to be more critical than vertical movement.

Abstract: In a multiple-span bridge structure with side-by-side bridges, a scaffolding girder-formwork assembly is movable in the longitudinal direction of each bridge for constructing individual sections of the superstructure over support piers. After use on one bridge, the scaffolding girder-formwork assembly is movable to the other bridge by first rotating it about a vertical axis from the longitudinal direction of the bridge to the transverse direction while the assembly is centered over a pier of the one bridge. A support for the assembly is moved over a pier on the other bridge. Then the assembly is moved in the transverse direction until it is centered over the pier of the other bridge. Subsequently, the assembly is rotated into the longitudinal direction of the other bridge in position for constructing sections of the superstructure.

Abstract: Long-span bridges, with the exception of the Silver Bridge failure at Point Pleasant, West Virginia have not exhibited serious problems with fatigue cracking and fracture. On occasion a stringer or floor beam has experienced cracking, which is a maintenance problem. When a main girder has cracked, the redundancy of the structure prevents collapse. Obviously, any cracked member is costly to repair and often restricts traffic until the repair has been completed. In general, the fatigue-crack problems that have developed in longer span structures are not significantly different from those experienced with shorter spans. Cracking has occurred at poor details, at large weld flaws, and from secondary and displacement-induced stresses. In this paper we present three case studies to examine the actual behavior of several large structures where fatigue cracking developed. One case examined is the cracking in stringer webs of a suspension bridge from out-of-plane displacement at floor beam connections. Strain measurements were obtained in order to assist with determining the cause of the cracking and to model the appropriate response. Further investigations were carried out on differently modified test bays in order to determine if the structural response could be altered so that further crack growth could be prevented or other courses or remedial action undertaken. The final two case studies examine the cracking at details where large lack-of-fusion regions have resulted and permitted fatigue-crack growth to occur. In one case, lack-of-fusion conditions at groove-welded splices in longitudinal stiffeners were investigated. In the second case, similar undesirable conditions existed at lateral bracing connection plates that were welded to girder webs and transverse stiffeners. These conditions permitted fatigue-crack growth to occur in the transverse connection of the lateral plate and stiffener and into the main girder web. The actual live-load stress range in longer span structures is generally of lesser magnitude and the frequency of occurrence is not as great as observed in shorter span bridges. Hence, it often takes longer for crack growth to develop in longer spans. Nevertheless, performance and behavior will eventually be impaired if fatigue-crack growth develops. Attention to details is shown to be of paramount importance in all bridge structures if fatigue and fracture are to be prevented.

Abstract: A considerable amount of literature in the past has been devoted to the aerodynamics of bridge structures by either analytical or experimental way. The main purpose of the paper is to introduce the wind characteristics and the aerodynamic response of structure observed at the specific bridges and to compare them with the theoretical results. The Kanmon Bridge and the Suehiro Bridge span 712m and 250m respectively and they are the longest in each type of bridge in Japan. The long-term observation systems were set up and put in operation at the early stage of completion of the bridges. After introducing the present status of the wind resistant design of long span bridges in Japan, the authors describe the wind characteristics, the lateral vibration of suspended structure and torsional and vertical bending vibration of bridge girder against gusty wind.

Abstract: Cable stayed advantages, span proportions, stay configurations, pylon arrangements, deck structure, and cable spacing and anchorages are discussed and developing design concepts are reviewed to provide data and information that allows more accurate comparisons to be made between cable-stayed and other types of bridges.

Abstract: Ramps to be connected by the folding bridge are fitted to railway or other tracks. The bridge is mounted at the end on one ramp, and swings between operative and track-clelaring positions. A guided bridge section is hinged to the bridge, at a point away from the swivel axis. This can be bent back, and adopts a horitonzal position in every bridge setting. It is pref. of the same length as the section hinged to the ramp. This enables a wide span to be bridged, with a unit which is compact in height.

Abstract: An analysis is made of the molecular weight dependence of the span of surface restricted self‐avoiding walks. Results for the normal as well as parallel components of the span for some cubic lattices are reported.

Abstract: A method for predicting the deviation angle at exit from the nozzles of an inward flow radial turbine using a streamline curvature method is given. Measurements of flow angles and stagnation and static pressures across the nozzle exit span of a small turbine have been made. The accuracy of the analysis is shown by comparison with experimental results. Finally, the developed theory has been used to show the possible effect on the deviation angle at exit from the nozzles of reducing the number of stator blades.Copyright © 1980 by ASME

Abstract: PURPOSE:In three supporting beams arranged above the bridge beam, a supporting bean having a central supporting beam suspended at both supporting beams as the guide extension beam is moved, a bridge beam is arranged per span and thereby a rapid and stable srranging operation is performed. CONSTITUTION:Extension beam 2 is jacked down from such a condition as a bridge beam 1a of one span is added to the bridge beam 1, then the extension beam is transferred to the subsequent section by the moving boggies 5 and 6. The supporting part 2a of the transferred beam 2 is fixed on the pier 12, this supporting part 2a is fixed on the pier 12 and supported at three points by the supporting part 2a and the boggies 5 and 6. Subsequently, the supporting beams 3 and 4 are jacked down together with the supporting beam 14, a frame is removed, the supporting beams 3 and 4 are transferred to the subsequent arranging section as a guide of the beam 2. Then, the supporting column 11 is connected to the beams 3 and 4 and supported on the pier 12, then jacked up. Then, the beam 2 is transferred in such a way as the same is slightly projected into the subsequnet arranging section, the beam 2 is jacked up, the frame is assembled, iron reinforcements are applied, then the concrete is applied, cured and the bridge beam 1b is arranged.

Abstract: The flexibility of supports influences the dynamic response of highway bridges. A computer model is presented, simulating the behaviour of a single span bridge on flexible supports and carrying a moving load. The bridge is treated as a prismatic beam. The load and supports are represented by a single axle sprung mass and by linear springs respectively. Normal mode analysis is used to obtain the equations of motion, which are integrated numerically. For practical ranges of parameters describing the bearings, bridge and vehicle, increased response is predicted only for very flexible supports. Surface roughness of the deck and approaches prove to be very important (a).

Abstract: Spanning the Stanislaus River in Northern California, this bridge includes a 640-ft center span that is the world's longest span in lightweight concrete and the longest bridge span ever built in the U.S. using the segmental cantilever construction method. Its use of economical lightweight concrete in the bridge superstructure is a unique design feature. The extraordinarily tall and graceful bridge rests on piers rising 350 feet above the stream bed. The height and length of the spans required long distance concrete pumping on a scale rarely attempted. The bridge is the best example in this country of a cast-in-place, segmentally constructed concrete box girder bridge.