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Flange. 一 Tho upper or lower chord of a beam. It is the principal part for resisting citbe* 
compression or tension. 
Flexure. 一 Bending. 
Floor Sy«tem. 一 That part of the bridge whicli directly receives the travel. 
Floor Heam, 一 A beam to support a portion of the floor aud its load. (Plate I. and Plate 
II., Fig. 10.) 
F. o. B. — Free on board ship, a term used in speaking of freight. 
Foot Plank. 一 A plank for walking upon. (Plates I. and III.). 
Forge. — An app.aratus for heating iron. (Plater XII., Fig. II.) 
Framing, 一 The carpenter work on timber. 
Girder. — Any structure to cross a chasm or opening. The term is generally applied to 
short structures for places wbere it is not advisable to uso trusses ； for instance, a plat« girded 
or a rolled girder. 
Guard Rati. 一 A rail to prevent a derailed train from running off a bridge. (Plate I し 
Fig. 14.) 
Guy*, or Guy TAnea, 一 Lines for bracing the top of a pole, derrick, or any similar apparatus. 
Ciyxntioii, — Seo radius of ffyration. 
Hammered Head. — a head formed on the end of a bar by hammering. 
Hand Liiios. — Small ropes used in erection. 
Headway. — See clear headway. 
Hinged Bnd. 一 An end of a strut connected only by a piu. 
i«p. — The place at which the top chord meets the batter brace. 
III I , Joint. "— The joint of tho top chord and batter brace. 
Hip Vertical. 一 A rod hung from tlio pin at tho hip for tho purpose of suspending the fl°° r 
beam. (Plate I.) 
Holding on Bar. — A lever to hold against one end of a rivet while the head at the other 
end is being formed with a button sett. (Plate XII., Fig. 16.) 
I-Beam. — A piece of rolled iron of the section shown on (Plate II., Fig. 2.) 
initial T«n«ion, 一 The tension caused in any adjustable member by screwing up the 
justing apparatus. 
intensity. 一 The intensity of a stress is the amount of stress upon a square inch of section* 
Intermediate strut. — An overhead strut in high bridges, attached to the posts of opposite 
trusses, and lying between the upper lateral strut and the floor. In deck bridges, if used at 
it would lie between the upper and lower lateral struts. (Plate I.) 
Jack Screw. 一 A machine for raising heavy weights. (Plate XII., Fig. 】 0.) 
Jaw. — A connection on the end of a strut similar to that shown on Plate II., Fig. 11 り 
Plate VIII., Figs. 7—10. 
•Joint, — A place where two abutting or lapping pieces are connected. 
Joist. — A beam. 
Knee or Knee Dracv. 一 See bracket. • 
Lacing. — A system of bars, not intersecting each other at the middle, used to connect tb 0 
two channels of a strut in order to make them act as one member. (Plate II., Fig. 11.) 
liacing-nar. — A bar belonging to a system of lacing. 
Lateral Rod. 一 A tension diagonal of a lateral system. (Plato I.) 
Ijateral Strut. — A compression member of a lateral system. (Plate I.) 
Lateral System. — A system of tension and compression members forming the web of 级 
horizontal truss connecting the opposite chords of a bridge. Its purposes are to transmit 
pressure to the piers or abutments, and to prevent undue vibration from passing loads. 
Latticing. — A_ system of bars crossing each other at the middle of their lengths, used to 
connect the two channels of a strut in order to make them act as one member. (Plate エ し 
Fig. 9.) 
Lattice Bar. 一 A bar belonging to a system of latticing. 
