▒ 공지 사항 ▒

*Itasca Newsletter - The Source - May 2022*


View this email in your browser

THE SOURCE An Itasca Newsletter


May 2022

Full Article
오늘 하루 숨김 [ 닫기 ]
STABILITY

STABILITY

STABILITY
제조원: 미국
상품코드: Latest
 

 


 

handling and Transportation 하는 동안의 long prestressed concrete beams의 안전율 해석 프로그램 The race for longer bridge span lengths with low initial costs continuously forces engineers to consider innovative design and construction alternatives. This trend is driven by many concerns, including safety (reduced number of supports/piers) and reduced maintenance costs (elimination of deck joints). Traditionally, prestressed/precast girders were not considered viable alternatives in the 150 – 300 feet span ranges. Besides prohibiting span-to-depth ratios, most states have restrictions regarding the maximum weight and length that can be transported on the highway system. As such, in concurrence with new construction and design methods (spliced girders), deeper, slender concrete girders have been developed to better accommodate this requirements. While the girders are getting longer deeper, and more slender, cracking due to additional tensile stress induced during girder handling and transportation creates and increased concern. Of equal concern is the problem of a beam entering in an unstable condition and rolling over along its longitudinal axis during transportation. To better understand the phases in a girders handling life, see the following photos: Conventionally, safe handling and stability of girders has been addressed only by contractors and precast producers, temporarily during construction. However, many difficulties and costly construction delays could be avoided if the designer would consider and check the lateral stability of beams during the design phase. To provide a consistent method for the evaluation of lateral beam stability, LEAP Software has developed STABILITY™, the first software program that calculates the factor of safety against these undesirable conditions during handling and transportation of long prestressed concrete beams with various support conditions. STABILITY™ will calculate the factors of safety against cracking and rollover, as well as stresses at critical points along the beam. STABILITY™ is built to comply with AASHTO LRFD Specifications Art. 5.5.4.3, and incorporates a theory first developed by long-time PCI professional member Mr. Robert F. Mast, which later became the basis of the PCI Design Handbook for lateral stability during lifting. The latest principles and full scale testing results, published by Mr. Mast in the PCI Journal in a two part article between 1989 and 1993, are also incorporated. Two different support conditions can be analyzed in STABILITY™: Beam handing from loops Beam supported on truck and trailer For increased efficiency, STABILITY™ also has the ability to evaluate designs of beams performed using CONSPAN LA™. Evaluate the behavior of a concrete beams through the principal stages during constructions: hanging from loops supported from underneath on a truck and trailer, including dynamic effects during transportation Evaluate the added wind effects in either of the two support cases Evaluate the effect of inclined cables used for hanging beams Compute the Factor of Safety against crack initiation and complete failure for beams hanging from loops Compute the Factor of Safety against crack imitation and rollover for beams supported on truck and trailer during transportation. Plot the variation of Factors of Safety against rollover and cracking in relationship to the overhang or support distance from the beam end Ability of us

 


 

 

 


 

 

 


 

 

 

리뷰 작성

이름:


리뷰: 주의: HTML 태그는 무시됩니다!

평가: 나쁨           좋음

보안입력 코드를 입력하십시오:




태그: STABILITY