noun
definition
A beam of steel, wood, or reinforced concrete, used as a main horizontal support in a building or structure.
definition
One who girds; a satirist.
Examples of girders in a Sentence
There are fifteen main transverse girders to each shore span, with nine longitudinal girders between each pair.
Where the rail-gauge is narrow and great weight is not desired, blocking girders are provided across the under side of the truck; these are arranged so that, by means of wedges or screws, they can be made to increase the base.
The principal component parts of a traveller are the main cross girders forming the revolving bridge, the two end carriages on which the bridge rests, the cranes.
With Edward Cooper (son of Peter Cooper, whom Hewitt greatly assisted in organizing Cooper Union, and whose daughter he married) he went into the manufacture of iron girders and beams under the firm name of Cooper, Hewitt & Co.
These girders are supported by the cables over the centre span but not in the side spans.
There are two high-level footways for use when the bascules are raised, the main girders of which are of the cantilever and suspended girder type.
The middle girders are 120 ft.
The main suspension chains are carried across the centre span in the form of horizontal ties resting on the high-level footway girders.
The suspension chains are constructed in the form of braced girders, so that they are stiff against unsymmetrical loading.
Transverse girders are hung from the chains at distances of 18 ft.
The anchor ties are connected to girders embedded in large concrete blocks in the foundations of the approach viaducts.
The two bascules are each constructed with four main girders.
Over the river these are lattice girders, with transverse girders 12 ft.
The girders carry a floor or platform either on top (deck bridges) or near the bottom (through bridges).
For railway bridges it commonly consists of cross girders, attached to or resting on the main girders, and longitudinal rail girders or stringers carried by the cross girders and directly supporting the sleepers and rails.
In the girders of bridges the horizontal girder is almost exclusively subjected to vertical loading forces.
But girders may have curved chords and then the stresses in the web are diminished.
The walls thus supported no load but their own weight, and were tied to the inner cage formed by the wall columns, interior columns, girders, and floors by anchors arranged to provide for the shrinkage of masonry in drying out which always occurs to a greater or less extent.
In such metal framework the beams and girders shall be riveted to each other at their respective junction points.
If pillars made of rolled iron or steel are used, their different parts shall be riveted to each other and the beams and girders resting upon them shall have riveted or bolted connexions to unite them with the pillar.
If cast-iron pillars are used, each successive pillar shall be bolted to the one below it by at least four bolts not less than three-fourths of an inch in diameter, and the beams and girders shall be bolted to the pillars.
At each line of flooror roofbeams, lateral connexion between the ends of the beams and girders shall be made by passing wrought-iron or steel straps across or through the cast-iron column, in such a manner as to rigidly connect the beams and girders with each other on the direction of their length.
These straps shall be made of wrought-iron or steel, and shall be riveted or bolted to the flanges or to the webs of the beams or girders.
The bracing is accomplished by the introduction at the angles of the columns and girders or beams of gusset plates or knee braces, or by diagonal straps or rods properly attached by rivet or pin connexions.
For girders of small spans " I " beams or channels are generally used, but for greater spans girders are built of riveted work.
In girders and beams the maximum fibre stress is usually limited to 16,000 lb.
In very short girders the shear must be computed, and in long girders the deflexion, particularly the flexure from the variable load, since a flexure of more than of the length is liable to crack the plastering of the ceilings carried by the girders.
The same necessity for computing shear and flexure applies to the floor beams. The floors between the girders are constructed of " I" beams, spaced generally about 5 ft.
Sometimes the beams rest upon the girders, and are riveted through the flanges to it; in this case the abutting ends of beams are spliced by scarf plates placed on each side of the webs and secured by rivets.
It is usual in both girders and beams to provide not only for the safe support of the greatest possible distributed load, but for the greatest weight, such as that of a safe or other heavy piece of furniture which may be moved over the floor at its weakest points, the centres of the girders and beams. It must always be borne in mind that the formulae for the ultimate strength of the " I " beams only hold good when the upper chord or flange is supported laterally.
The Broad Flange Differdange Beams are claimed by the manufacturers to be stronger and to minimize weight for use as girders; they are made in twenty-one different sizes with flanges from 88 to i 2 in.
The arrangement of the building and floor framings is in a great measure governed by the architectural effect sought and by the arrangement and proper planning of the interior according to the intended uses; the positions of columns, girders and floor beams are usually the result of particular requirements, and unless complicated and expensive framing is to be expected the distance between columns must be kept within the limits of simple girder construction.
The position of the columns having been determined, the girders must next be located; these serve to support the floor beams which transfer the loads direct to the columns, and also to brace the columns during erection.
Truss rods, portals, or lattice or plate girders constitute the more definite types of wind-bracing ordinarily employed; the bracing must reach to some solid connexion at the ground.
The filling between the girders and floor beams consists of segmental arches of brick, segmental or flat arches of porous (sawdust) terra-cotta, or hard-burned hollow terra- - cotta voussoirs, or various patented forms of con crete floors containing ties or supports of steel or iron.
In flat forms of masonry floor construction the level of its bottom is placed somewhat below the bottom of the " I " beams and girders, so that when it is plastered a continuous surface of at least an inch of mortar will form a fire-proof protection for the lower flanges of the beams and girders.
Girders projecting below the floor are usually encased in from z to 2 in.
It is important in all fire-proofing of columns and girders, and in all floor construction, furring and partitions, that there shall be no continuous voids, either vertical or horizontal, which may possibly serve as flues for the spread of heat or flame in case of fire.
The Dynamic Avon The single cable forms a graceful curve to support bridge girders without blocking the view creating a gorgeous landscape.
Later, wrought-iron box girders gave way to plate girders.
When the chains were in place vertical suspension rods were added before the two huge girders were added by two mammoth cranes.
The hand rails are bolted to the main girders.
The struts of the high girders, which plunge down from the top like the tracks of a rollercoaster, are not absolutely straight.
An 1876 drawing of the River Avon Bridge, showing the original ornate lattice girders.
The earliest iron truss bridges were evolved from the plate girders which came into use all over Great Britain in the railroad age.
The floor system is built on the customary method of heavy cross girders and longitudinal stringers.
The Ordish bridge built at Prague in 1868 had oblique chains supporting the stiffening girders at intermediate points of the span.
These results are for the centre deflections of main girders, but Stone infers that the augmentation of stress for any member, due to causes included in impact allowance, will be the same percentage for the same ratios of live to dead load stresses.
A purely empirical allowance for impact stresses has been proposed, amounting to zo% of the live load stresses for floor stringers; 15 for floor cross girders; and for main girders, io% for 40-ft.
In a three-span bridge continuous girders are lighter than discontinuous ones by about 45% for the dead load and 15% for the live load, if no allowance is made for ambiguity due to uncertainty as to the level of the sup ports.