▁beam - to - column ▁joint s ▁needs ▁to ▁be ▁increased ▁in ▁concrete ▁structures . ▁In ▁many ▁brid ges , ▁the ▁amount ▁of ▁steel ▁required ▁by ▁the ▁se ism ic ▁code ▁causes ▁con g estion ▁at ▁the ▁joint s . ▁To ▁alle vi ate ▁this , ▁steel ▁fib ers ▁can ▁be ▁used ▁as ▁rein for cement ▁to ▁improve ▁the ▁bond ▁between ▁the ▁reb ars ▁and ▁the ▁surrounding ▁concrete . ▁Test s ▁have ▁shown ▁that ▁by ▁using ▁steel ▁fi ber ▁rein for ced ▁concrete , ▁the ▁anch orage ▁length ▁of ▁re bar ▁can ▁be ▁reduced ▁while ▁impro ving ▁she ar ▁and ▁flex ural ▁capac ities . ▁The ▁reduced ▁anch orage ▁length ▁required ▁reduces ▁the ▁con g estion ▁at ▁beam - to - column ▁joint s . ▁ ▁Another ▁adv ancement ▁is ▁in ▁the ▁use ▁of ▁prest ress ed ▁concrete . ▁ ▁Pr est ress ed ▁concrete ▁is ▁a ▁major ▁advance ▁in ▁concrete ▁engineering ▁and ▁has ▁effectively ▁been ▁used ▁in ▁rig id ▁frame ▁bridge ▁construction . ▁ ▁This ▁is ▁notable ▁because ▁it ▁was ▁already ▁challeng ing ▁to ▁place ▁standard ▁rein for cing ▁in ▁a ▁concrete ▁rig id ▁frame ▁bridge . ▁ ▁Pr est ress ing ▁the ▁reb ars ▁is ▁more ▁difficult ▁but ▁was ▁proven ▁to ▁still ▁be ▁feas ible . ▁ ▁Pr est ress ed ▁concrete ▁is ▁useful ▁in ▁bridge ▁construction ▁because ▁it ▁has ▁higher ▁tens ile ▁strength ▁than ▁traditional ▁rein for ced ▁concrete , ▁allowing ▁for ▁longer ▁bridge ▁sp ans . ▁ ▁Br id ges ▁are ▁frame ▁structures ▁which ▁are ▁used ▁to ▁help ▁people