Showing papers on "Deck published in 1974"

Indicial aerodynamic functions for bridge decks

Abstract: With certain classical results for airfoils as a guide, lift and moment functions of the indicial type are derived for suspension bridge deck sections of either the open truss or streamlined variety. Bluff deck sections susceptible to coherent vortex shedding are not treated. The indicial functions are obtained analytically from the experimentally-derived linear-theory flutter derivatives of the bridge deck sections in question. The method used is nonlinear least squares, wherein a prescribed exponential form with unknown coefficients for the indicial function is determined by fitting transformed counterparts of it to the corresponding experimental flutter derivative curves. Several examples of indicial moment functions of bridge deck sections are presented. These offer rather conclusive proof that Wagner or thin airfoil theory alone is inadequate for application to bridge buffeting flutter and buffering analyses.

Floor for sports and in particular for roller skating

Abstract: A floor for roller skating or other sports activities and the like consists of extruded metal deck sections of a required length which are placed side-by-side on an even solid surface. Juxtaposed plastic tiles or plates are laid down on the deck sections and are provided on their bottoms with press studs which interlock with continuous channels or grooves formed in the deck sections. Each plastic tile or plate engages at least a pair of the underlying deck sections and thus the tiles serve to secure adjacent deck sections in assembled relationship in the formation of a continuous floor.

Tanker structural analysis for minor collisions

Abstract: In a study of the behavior of a longitudinally framed oil tanker structure during a minor collision in which the cargo tank remains intact, a plastic analysis procedure, based partly on model tests and inspections of collision damage, was developed and applied to a limited number of idealized ship collisions. The mathematical model of the analysis procedure follows the various phases of structural behavior of the struck ship occurring as a collision progresses--bending and stiffener buckling of the stiffened hull plating followed by membrane stretching, web frame failures, etc., up to hull rupture. Both single- and double-skinned ships were studied. Parametric analyses using the analytical procedure have indicated that most (typically between 2/3 and 9/10) of the energy absorbed during a collision is that of membrane tension in the stiffened hull. Other significant energy absorbed is that of memebrane tension in the stiffened deck and in-plane shearing of web frames.

Pipe-and-ball truss array

Abstract: An improved pipe-and-ball truss array for supporting a deck surface, such as a roof deck or a wall panel, thereon in a predetermined plane is provided in which the outer chord of the truss array comprises an outer hollow pipe element having a structural tee element extending radially outward from the outer surface thereof in a plane normal to the plane in which the deck surface is to be supported on the truss array and an inner rod running through the pipe along the longitudinal axis thereof. A hollow substantially ball-like member, such as a hollow spherical member, is provided which is common to a plurality of truss members which truss members are joined to the spherical member by bolting. The structural tee element comprises a radially extending portion and a first planar extending portion normal thereto, with the first planar extending portion extending in a plane parallel to the deck surface supporting plane and being capable of structurally supporting the deck surface thereon above the outer hollow pipe element. The outer hollow pipe elements which have such radially extending structural tee elements are structurally stronger in bending than the outer hollow pipe elements which do not and preferably extend in a direction normal to the direction in which the deck surface to be supported runs. The structural tee element may also include a second planar extending portion disposed above and spaced from the first planar extending portion and extending in a plane parallel thereto for supporting the deck surface between the first and second planar extending portions. The deck surface can thereby be readily supported on the improved truss array, which is an improvement on the array disclosed in commonly owned U.S. Pat. No. 3,882,650.

Unitary plastic pallet for handling heavy powder loads

Abstract: A lightweight, unitary plastic pallet adapted for handling heavy powder loads. The pallet has a substantially rigid lower deck, a flexible, reinforced and continuous upper deck adapted to deflect against the lower deck under load, and a plurality of integral legs permitting forklift transport of the pallet.

Finite Element Analysis of Metal Deck Shear Diaphragms

Abstract: A special adaptation of the finite element method provides a basis for the analysis of shear diaphragms composed of light gage steel panels. The panels, perimeter beams, purlins, and connectors are chosen as the basic elements, and their mechanical properties established. They are then incorporated as parts of an analytical model using matrix methods. The predictions of analysis are compared with experimental results.

Non-heeling hull assembly

Abstract: A boat including a hull having a deck and bottom, a sail carrying mast, and a keel structure, with the mast and keel being pivotally supported from the hull and so operatively connected by hydraulic or mechanical means that when the boat is wind driven the mast may tilt to port or starboard with concurrent pivoting of the keel structure in an opposite direction. Pivoting of the mast and keel structure is independent of the hull, and the hull remaining in a non-heeling position when the boat is wind driven at a substantial rate. The mast when used on a small boat may be provided with a break away section adjacent the pivotal support therefor, and as a result the mast and supported sail will break away and fall to the side of the boat if the latter is caught in a squall or sudden heavy gust of wind, rather than the boat being overturned.

Dockboard safety stop

Abstract: A dock leveler having a swingable ramp or deck positioned for engagement with a truck bed. The deck is freely swingable through a selected angle, both above and below a horizontal position, to accommodate and compensate for various bed heights. To prevent the deck from falling in the event a load is positioned on the deck and the truck pulls away from the deck, an improved safety stop device is positioned for coaction with the deck. The safety stop device, in a preferred embodiment of the invention, comprises a pair of closed and self-contained hydraulic stop cylinders positioned for engagement with the opposite edges of the deck. The stop cylinders are load sensing and permit free swinging movement of the deck under light loads, but positively prevent free swinging movement of the deck when same is heavily loaded.

Railroad car for transporting automobiles

Abstract: A railroad car is provided for transporting automobiles by rail by carrying the automobile cargo at multiple levels with some of the automobiles on the car floor and with the remaining automobiles resting on horizontal decks cantilevered from vertical structures. The horizontal decks are individual decks extending only the width of the car. The spaces between the decks on which the automobiles rest are sized so that the roof of an automobile on a lower level may protrude through the plane of the next higher deck. The railroad car is designed to permit loading automobiles from either side of the car by use of an external loading mechanism.

Railway car hinge-deck lock

Abstract: A multi-level auto rack railway car includes a deck having an end hinge section provided with an improved locking mechanism operable to engage and lock the hinge deck sections in either an elevated or lowered position. A pre-stressed lock rod anchored to the car includes a lock plate having alternate locking portions selectively displaceable to engage a catch plate on the hinge deck section while a pre-stressed spring facilitates vertical movement of the deck section upon actuation of the lock rod.

Deck structure for vehicles

Abstract: A deck structure for use in supporting articles at an intermediate level spaced upwardly from the bed of a vehicle. In a first embodiment the deck structure comprises a first section pivotally connected at the intermediate level and adapted to be moved between a vertical position adjacent a side wall of the vehicle and a horizontal position extending outwardly from the side wall. A second section of the deck is pivotally connected to the first section, and this second section is adapted to be vertically positioned adjacent the side wall in a position extending opposite the position of the first section. The second section is adapted to be pivoted relative to the first section during pivoting of the first section to the horizontal position whereby the second section can also be moved to a horizontal position to complete the span between the side walls of the vehicle thereby providing a deck at an intermediate level. A second embodiment utilizes a unitary deck structure adapted to move between the vertical and horizontal positions. A third embodiment employs a telescoping deck structure.

Deck structure and method for building same

Abstract: A deck structure is assembled on a base structure which extends upwardly out of a body of water and is supported on the bottom of the water body. The deck structure is separately constructed as a self-supporting horizontal unit at a building site such as a pier, and floating barges are provided for supporting the deck structure outwardly of the building site. The deck structure is thereafter transferred to the base structure by means of the barges.

Support column and disposable pallet structure

Abstract: A support column for disposable pallet or unitized container construction utilizing molded legs which cooperate with deck members to support said deck and materials placed thereon. The legs are frustums which have flanges positioned below the material support deck of the pallet or container and about the larger end of the frustum. The larger end of each leg extends upwardly into an opening in the material deck, and tabs are formed on the leg for securing the leg to the deck such that upon movement of the deck by a fork lift the leg will stay firmly attached. The pallet construction may utilize a second deck similar to the material support deck which is secured to the smaller end of the pallet leg by a support ring. The similar structure of the second deck avoids the number of different pieces necessary in constructing a pallet and the support ring supports the smaller end of the pallet leg to avoid pivoting of the larger end of the leg in the opening of the support deck.

Building deck construction

Abstract: A poured building deck structure having sheet metal structural shapes of a box section as sub-purlins, the upper face of the box section having open slots for engaging sheet metal clips which are secured in the box section when the axis of the clip and the box section are about 90* to each other, the clip engaging and holding formboard adjacent the top face of the box section and the clips then extending substantially vertically upward and then extending substantially horizontally engaging the poured concrete above the formboard to provide uplift resistance to the composite structure. The poured building deck structure of this invention is extremely versatile providing a very economical insulating and fireproof poured gypsum deck structure. The combination structure of this invention permits the use of thinner formboard and thinner concrete, providing lighter weight decks than previously available.

Transport vessel for floating onloading and offloading of cargo

Abstract: A vessel for transporting floatably onloaded and offloaded cargo (typically barges) is disclosed. A hull having a well deck surrounded on three sides by the bow, port and starboard vessel's sides has a plurality of ballast tanks adapted to be filled with sea water. When the ballast tanks are flooded, the hull is in a loading configuration wherein the well deck is submerged so that cargo can be floated over the well deck and positioned thereon. At this submerged position of the well deck, the continuous sidewalls of the vessel are interrupted by a series of horizontally elongate water level ports constituting a large interruption of the water plane of the vessel. These ports are concentrated in the area of the forward well deck bulkhead and impede the formation of standing waves within the vessel whereby destructive motion between the carrier vessel and the floating cargo can be prevented from damaging the carrier vessel, floating cargo, or both. As the vessel is raised to bring the well deck in contact with the floating cargo, these surge ports are raised above the waterline and no longer communicate the well deck to the sea. Thereafter, communication to the sea for drainage only is provided by vertical freeing ports, constituting a relatively small interruption to the water plane of the vessel.

Method of setting tile and forming swimming pool deck

Abstract: A method of setting tile along an upwardly extending wall of a swimming pool or the like, and for forming a concrete deck along the upper edge of such wall in overlying relation therewith. The tile-setting and deck-forming may be effected as a single-stage or multiple-stage process; and in either instance, a plurality of tile units are supported a spaced distance from the wall in side-by-side juxtaposition to form a generally horizontal row. The space intermediate the tile units and pool wall is filled with a mass of mortar which is maintained therein to cure and to bond the tile units to the wall. In a one-stage process, the mortar used to bond the tile to the wall is supplemented in sufficient quantity to provide the requisite concrete mass that cures into a deck overlying the upwardly extending pool walls. In a two-stage process, the concrete mass that cures to form the deck is poured after the mortar and as a separate operation.

Adjustable metal scaffold

Abstract: A scaffold module having a first section comprising a horizontal deck having a tongue of reduced width extending outwardly from one end of the deck, a middle section comprising an elongated horizontal deck having a tongue of reduced width at one end of the deck and a support means extending outwardly from the second end of the deck, said first section tongue being in slidable contact with the top of the support means, and with the bottom, of the middle section deck, and a third section comprising a horizontal deck and a support means extending outwardly from one end of the deck, said middle section tongue being in slidable contact with the top of the support means, and with the bottom, of the third section deck

Platform weighing scale

Abstract: A platform weighing scale in which a reinforced load cell-supported platform structure has a framelike reinforcement cooperating with a load-receiving deck or platform to define a torsion box frame which resists load-induced deflection of the platform between spaced apart load cell support points. FIELD OF INVENTION This invention relates to platform weighing scales and is particularly concerned with platform structures which are especially suitably for low profile type platform scales. BACKGROUND Low profile platform scales for weighing relatively heavy loads are characterized by having a relatively small overall height as measured from the floor or other scale-support surface to the top of the load-receiving platform or deck. Scales of this type are especially suitable for weighing loads which are carted by such vehicles as tote bins, push carts, dollies, fork lift trucks and other usually relatively small motor vehicles. Low profile type platform scales normally do not require installation in a pit to accommodate load-carrying vehicles and roll-on loads in general because the platform is relatively close to the floor surface and can easily be accessed by relatively short, gently sloped ramps. Thus, low profile type platform scales offer the significant advantage of pitless installation. On the other hand, in installations where it is desired to locate the platform flush with the floor surface, only a shallow pit is needed. One of the stuctural features which contribute significantly to the floor-to-platform height of prior platform scales is the construction of the platform itself. Typically, the platform in prior scales is a relatively thick structural deck plate which is reinforced by several structural beams on the underside to minimize the deflection or sag of the platform under the influence of loads on the platform. Load-induced deflection of the platform is objectionable in platform scales of the type in which the platform is supported on load cells because the deflection of the platform impairs the accuracy of weight measurements. When the platform deflects or sags under the influence of an applied load the supported corners of the platform curl up to effectively rotate over the load cells. As result, the force transferred by the platform to the load cell rotates away from a vertical line and out of axial alignment with the load cell. This force displacement results in the application of a horizontal force component to the load cell to side load the cell. Since load cells are usually incapable of measuring the horizontal component and since spurious output result from sideloading, the accuracy of the weight-indicating output voltage of the cell will be impaired to extent of the side loading. The customary solution to this problem has been to make the deck plate thick enough and/or to make the deck plate reinforcement strong enough to minimize the deflection of the platform under the influence of applied loads. Such a solution, however, results in platform structures of increased height. It therefore is not compatible with the objective sought in low profile platform scales, namely the minimization of the height of the scale from the support floor to the load-receiving platform surface. Another solution to the platform deflection problem is described in U.S. Pat. No. 3,587,761 which issued on June 28, 1971 to L. C. Merriam et al. This solution however, significantly increases the floor-to-platform height of the scale because it requires a special structure to be interposed between each load cell and the platform to avoid side loading of the cells. The foregoing U.S. patent also illustrates a typical platform structure having a deck plate and reinforcing beams which are seated on the platform-supporting load cells. Other examples of prior weighing scales are shown in U.S. Pat. No. 3,103,984 which issued to C. L. Ellis et al on Sept. 17, 1963, U.S. Pat. No. 2,962,276 which issued to A. L. Thurston on Nov. 29, 1960, U.S. Pat. No. 3,679,011 which issued to I. M. Hawver on July 25, 1972 and U.S. Pat. No. 3,565,196 which issued to E. Laimins on Feb. 23, 1971. SUMMARY & OBJECTS OF INVENTION In the novel platform scale of this invention, the load-receiving platform structure is reinforced in such a manner that it has an extremely low overall height, but yet has a high degree of torsional rigidity to effectively resist load-induced deflection and rotation of the platform in the regions of the platform-supporting load cells without resorting to excessive deck plate thicknesses. Accordingly, a major object of this invention is to provide a novel load cell platform scale in which the load-receiving platform or deck is reinforced in such a manner that it has an extremely low height, but yet affords a high degree of torsional rigidity to effectively resist load-induced deflection and rotation of the deck in the regions of the platform-supporting load cells. Another important object of this invention is to provide a novel scale platform structure which is suitable for low profile platform scale applications and which is reinforced in such a manner to effectively resist deflection under the influence of an applied load. In the illustrated embodiment of this invention, the foregoing objects are achieved by a horizontal framelike reinforcing structure which is positioned vertically below the load-receiving deck to underlie border regions of the deck and which is rigidly joined to the deck by reinforcing structural side members. This reinforcing structure cooperates with the deck to define in vertical cross section a torsion box arrangement which has a closed perimeter. The upper and lower walls of the torsion box are spaced vertically apart and are respectively defined by the deck itself and the framelike reinforcing structure. The sides of the torsion box arrangement are closed by the above mentioned structural side members which are rigidly joined to the deck and to the framelike reinforcing structure. With the foregoing construction, the internal shear flow developed by an applied load will be in opposite directions through the upper and lower walls of the closed box arrangement to create a torsion or twisting couple which resists load-induced deflection or sagging of the deck. In this way, curling and effective rotation of the corners of the deck in the regions of the load cells is resisted to minimize rotation of the load-induced forces which are transferred through the deck and applied to the load cells. The maximum height of reinforced platform structure of this invention is from the bottom face of the framelike reinforcing structure to the upper load-receiving face of the deck. Since the deck and framelike reinforcing plate structure need only be spaced slightly apart to provide a torsion couple moment of sufficient magnitude, the overall height of the reinforced platform structure will be very small. The reinforced platform structure of this invention is therefore particularly suitable for low profile type platform scales. Additionally, the arrangement of the reinforced platform structure with the platform-supporting load cells is such that the upper ends of the load cell force-receiving elements are each at a level which is higher than the lowest surface of the reinforcing structure. With this construction the overall height of the combined assembly of the load cells and the reinforced platform (as measured from the bottom faces of the load cells to the load-receiving deck surface) is less than the sum of the heights of the reinforced platform structure and one of the load cells. With the foregoing in mind, a more specific object of this invention is to provide a novel combined load cell and reinforced load-receiving platform assembly wherein the load-receiving platform or deck is reinforced by a framelike structure which underlies border regions of the platform and which is rigidly joined to the platform by reinforcing structure to defined a box-like arrangement in vertical cross section. Another more specific object of this invention resides in the provision of a combined load cell and reinforced load-receiving platform assembly in which a novel reinforcing structure cooperates with the load-receiving deck or platform to define a torsion box frame in which torsion or twisting couples are developed by an applied load to resist sagging or deflection of the reinforced platform between its load cell support points. Further objects of this invention will appear as the description proceeds in connection with the appended claims and below-described drawings.

Ultimate load test of a segmentally constructed prestressed concrete i-beam

Abstract: Test results of a segmentally constructed prestressed concrete bridge I-beam are presented. The test girder was manufactured from short precast segments which were joined together and post-tensioned, after which a deck slab was cast on the top. The girder, 92 feet long, was cast in eleven segments: nine segments of eight feet each and two end blocks of ten feet each. The assembled girder was then post-tensioned using two bonded tendons. The girder was made composite with a six-inch thick, six-foot wide, cast-in-place deck slab. The composite girder was then load tested, predominantly in flexure and its behavior, under working, cracking, and ultimate loads is reported. It is concluded that the performance of the segmentally constructed girder, under service as well as ultimate load, is comparable to that of a monolithic girder. /Author/

Securing system for jet engine testing of aircraft

Abstract: An anchoring device secures jet aircraft to a carrier during full power testing of the engine. A chock-like fitting is adapted to be secured flush with the upper surface of the deck of an aircraft carrier to be used for a tie down of aircraft undergoing full power engine run-up testing. The chock-like fitting includes a pivotally attached cover plate which closes over the chock at a level flush with the deck when the chock is not in use. When open, the cover plate exposes a slot-type aperture leading to a receiving cavity below the carrier deck. The aircraft attachment comprises a T-bar which is inserted into the fitting aperture and rotated 90* to position it within the receiving cavity.

Videotape cassette automatic loader-unloader

Abstract: An automatic loader-unloader of cassettes to and from a videotape deck in which the unloader comprises means to tilt and support the videotape with its top surface at a selected angle to the horizontal, and providing a shelf in front of the deck with the shelf co-planar with the top surface of the deck. Loading means are provided by means of an arm mounted above and parallel to the deck surface with means adapted to press against the back edge and top surface of the cassette when mounted on the shelf, so as to provide two components of force, one parallel to the plane of the cassette, causing it to move off the shelf and on to the elevator plate of the tape deck, and a second force perpendicular to the surface of the cassette so that when the deck is positioned on the elevator, and extends the eject spring, the downward force will cause the elevator to move downwardly and into the recording position. To unload the deck there are means to operate the eject lever on the tape deck, which lifts the elevator to move to its upper position, and the eject plate exerts a force on the cassette to move it forwardly, off the elevator plate from which it falls, by gravity, along the surface of the elevator and of the shelf, to be positioned on the shelf.

Roof drain arrangement

Abstract: A roof drain arrangement for use in a roofing system including a horizontal roof deck and a built-up roof thereon is disclosed herein. The arrangement includes a vertical roof deck connector, a tubular drain pipe connector, and a vertically extending and vertically adjustable drain tube. The arrangement also includes a strainer located over and around the top end of the drain tube.

Roll stabilizer for a boat

Abstract: A passive roll stabilizer for a boat in which a freely movable weight is supported for movement athwartships at a substantial distance above the deck on a mast or other superstructure. The weight is freely movable along an axis substantially parallel to the deck between widely spaced limits. The limits are defined by energy dissipating stops, such as spring-loaded dash pots or self-restoring plastic foam material.

Process for construction of bridges, in particular motorway flyovers

Abstract: For constructing a bridge having two successive piers and a continuous deck resting thereon and made of consecutive prefabricated segments, two deck portions or ''''beams'''' - each of which rests upon a provisional horizontal platform via vertical jacks, over the upper face of each of the two piers and out of contact with said face- are separately prepared, then assembled together by horizontally moving said two deck portions towards each other and fastening them together, the continuous deck thus formed being then lowered by means of the jacks until it rests on the two piers.

Repair of hollow or softened areas in bridge decks by rebonding with injected epoxy resin or other polymers

Abstract: The objective of this project was to develop a repair technique for bridge deck delaminations which could be used by highway maintenance personnel. The technique was to epoxy resin into the deteriorated areas to bond them back into a monolithic form with strength equal to or greater than the original deck. Equipment has been developed which makes the injection of epoxy into bridge deck delaminations (hollow planes) practical. The equipment is simple in design and can be operated with a minimum of training. The operational procedure is given in the report. The equipment costs about $2000 and plans are given in the report. Four concrete crack grouting epoxies have been lab and field tested. All four can be injected into hollow planes, but only two are believed to be satisfactory and one of these appears to be best. A performance specification has been developed: The most satisfactory epoxy tested meets this specification the other three do not. The long term durability of the repair technique has not been evaluated. But, the limited experience gained in this project and the previous project together with many long term successes in crack grouting type repairs makes chances look most promising. The cost of repair of a typical Interstate underpass structure with about 5% delaminated area has been estimated at less than $1000. The technique is best suited for use as a continuing maintenance procedure, rather than a one time reconstruction process. /Author/

Test to failure of a prestressed concrete bridge

Abstract: The test to failure of two spans of a simple span, prestressed concrete highway bridge is described, and the measured and computed load-deflection curves for the bridge are presented and compared. The calculated load-deflection curve, based on strain compatibility relationships, compares reasonably well with the curve obtained experimentally. Severe dishing of the deck slab led to a separation between the bridge deck and the girders; the result was a loss of composite action and subsequent shear failure of the girders. Questions are raised regarding the state of existing knowledge of the behavior of composite, prestressed concrete, multi-beam bridges.

Trials of experimental orthotropic bridge deck panels under traffic loading

Abstract: TWO EXPERIMENTAL ORTHOTROPIC DECK PANELS WERE STUDIED WHILE SUBJECTED TO NORMAL TRAFFIC ON A TRUNK ROAD. THE BEHAVIOUR OF 38MM MASTIC ASPHALT AND 9MM RESIN BASED SURFACINGS WERE COMPARED. THE STRESSES GENERATED BY MOVING VEHICLES WERE MEASURED AND FOUND TO BE CONSIDERABLY REDUCED ON THE PANEL SURFACED WITH ASPHALT RELATIVE TO THE PANEL SURFACED WITH RESIN-BASED MATERIALS. THE COMPOSITE ACTION OF THE MASTIC ASPHALT WITH THE STEEL DECK PANEL WAS INVESTIGATED OVER A RANGE OF VEHICLE SPEEDS AND SURFACING TEMPERATURES. RECORDS OF VEHICLE LOADING AND SURFACING TEMPERATURE WERE MADE THROUGHOUT THE TRIALS. AFTER FOUR YEARS FATIGUE CRACKS DEVELOPED IN THREE STIFFENER TO CROSS-BEAM WELDS ON THE PANEL SURFACED WITH RESIN-BASED MATERIALS. THESE WERE FOUND TO BE DUE TO STRESSES GENERATED BY TRAFFIC AND ALSO INFLUENCED BY AN INADEQUATE STANDARD OF WELDING. WHEN THE SITE WAS CLOSED AFTER MORE THAN NINE YEARS OF TRAFFIC LOADING ADDITIONAL STIFFENER TO CROSS-BEAM WELDS IN THIS PANEL HAD CRACKED. AT THE END OF THE TRIALS THE MASTIC ASPHALT SURFACING REMAINED IN GOOD CONDITION BUT THE RESIN-BASED SURFACINGS HAD BECOME UNSERVICEABLE. /AUTHOR/

Rotary drum filter with wire deck, apparatus and method

Abstract: In rotary drum filters wherein the filter drum has a wirewound deck providing support for the surrounding filter media, a novel method and system of tension winding and securing the deck wire with the aid of improved anchoring means for non-slidably yet detachably securing the wire at predetermined points along the length of the drum, whereby creeping and loosening of the wire windings is obviated. This also permits simplifying and speeding up the winding operation, as well as the replacement of individual wire sections between anchoring points.

Construction and testing of an experimental prestressed concrete bridge

Abstract: An experimental prestressed concrete I-beam bridge has been constructed as an integral part of the Pavement Durability Test Track Facility at the Pennsylvania State University. This two-span bridge has been instrumented and is being tested to evaluate the behavior of two different deck types. One span of the bridge was constructed with a conventional reinforced concrete composite slab. Wood forms were used on one-half the span, and metal stay-in-place forms on the other half. The other span was constructed with precast, prestressed concrete plank forms, topped with cast-in-place concrete. Instrumentation consisted of strain gages on the slab and beams and deflectometers on the beams. The bridge was loaded with a semi-trailer truck having maximum wheel loads of 17 kips. Measurements indicated that composite action was developed between the concrete plank and the cast-in-place topping. Full composite action was also developed between the beams and deck for both spans. Future tests include one million cycles of an equivalent 18 kip axle load, and overload tests. /FHWA/

Power windshield for boats

Abstract: A boat having a novel windshield construction is presented by the present invention. First and second opposed windshield sections are mounted on the forward deck at an acute angle to the keel of the boat. The opposing ends of the two sections mount channel-presenting tracks which receive a third windshield section of generally V-shaped configuration. This third section is movable from a raised position beneath the deck. In the raised position the third section cooperates with the first and second windshield sections to present a completed boat windshield of a streamlined V-configuration. When the third windshield section is lowered beneath the deck, an entryway onto the deck from the center of the boat is presented. The third section is moved by an electric motor coupled with it and a drive sprocket powered by the motor. A chain extending from beneath the deck toward the keel presents a gear track along which the sprocket runs. Appropriate stops limit movement of the third section in each of its two directions of movement.