Rolled shapes and built-up beams and girders can be subjected
to local concentrated compressive loads acting in
the plane of the web. Such loads can occur either over supports
or between supports of beams and girders. Chapter J of
the 2010 AISC Specification (AISC, 2010) recommends the
use of either single- or double-sided minimum half-depth
transverse web stiffeners or web doubler plates where web
crippling strength is less than design concentrated load.
Commentary on the AISC Specification mentions that
because the web crippling phenomenon has been observed
to occur in the web adjacent to the loaded flange, a halfdepth
stiffener (or stiffeners) or a half-depth doubler plate
is needed to eliminate web crippling. Research conducted
at the University of Maine (Salkar, 1992), however, clearly
showed that web crippling can occur in webs having halfdepth
stiffeners. Therefore, it is important that formulas
or procedures are made available for evaluating crippling
strength of webs with partial-depth stiffeners.
Although Chapter J of the 2010 AISC Specification has
formulas for predicting strength of unstiffened webs and
stiffened webs with full-depth stiffeners under local compressive
loads, it does not have any formula to predict crippling
strength of webs with partial-depth stiffeners under
local compressive loads. Research on the behavior and
design rules of intermediate transverse stiffeners attached
on web panels was summarized by Lee et al. (2002, 2003).
Research on the requirements of transverse stiffeners in
straight and horizontally curved steel I-girders was summarized
by Kim et al. (2007). Research on unstiffened webs
under compressive edge loads was summarized by Elgaaly
(1983). Research on the same topic post-1983 was summarized
by Salkar (1992) at the University of Maine.
This paper highlights part of the research at the University
of Maine and gives recommendations based on the results of
this research. This paper also presents a brief comparison of
provisions of the 2010 AISC Specification, Canadian codes
(CSA, 2006) and Australian (AS, 2012) codes with respect
to crippling strength of stiffened webs under local compressive
loads.
This paper addresses the strength of stiffened webs of
rolled shapes under local compressive patch loads between
supports. Three types of local compressive patch loading
have been considered:
1. Loading through roller on top flange as shown in
Figure 1.
2. Loading through patch plate on top flange as shown in
Figure 2.
3. Loading through I-shaped beam on top flange as
shown in Figure 3.
รูปร่างรีดและคานที่สร้างขึ้นและคานสามารถภายใต้แรงอัดความเข้มข้นในท้องถิ่นทำหน้าที่ในระนาบของเว็บ โหลดดังกล่าวสามารถเกิดขึ้นได้ทั้งในช่วงการสนับสนุนหรือระหว่างการสนับสนุนของคานและคาน บทเจ2010 AISC แนะนำให้ใช้อย่างใดอย่างหนึ่งเดียวหรือสองด้านไม่ต่ำกว่าครึ่งหนึ่งของความลึกขวางเว็บหรือเว็บstiffeners แผ่นที่เว็บทวีความแรงทำให้หมดอำนาจน้อยกว่าการออกแบบที่มีความเข้มข้นในการโหลดความเห็นเกี่ยวกับ กล่าวว่าเนื่องจากเว็บปรากฏการณ์พิการได้รับการปฏิบัติที่จะเกิดขึ้นในเว็บที่อยู่ติดกับหน้าแปลนโหลดเป็นhalfdepth ทำให้แข็ง หรือแผ่นทวีครึ่งเชิงลึกที่จำเป็นในการขจัดเว็บทำให้หมดอำนาจ Rolled shapes and built-up beams and girders can be subjected
to local concentrated compressive loads acting in
the plane of the web. Such loads can occur either over supports
or between supports of beams and girders. Chapter J of
the 2010 AISC Specification (AISC, 2010) recommends the
use of either single- or double-sided minimum half-depth
transverse web stiffeners or web doubler plates where web
crippling strength is less than design concentrated load.
Commentary on the AISC Specification mentions that
because the web crippling phenomenon has been observed
to occur in the web adjacent to the loaded flange, a halfdepth
stiffener (or stiffeners) or a half-depth doubler plate
is needed to eliminate web crippling. Research conducted
at the University of Maine (Salkar, 1992), however, clearly
showed that web crippling can occur in webs having halfdepth
stiffeners. Therefore, it is important that formulas
or procedures are made available for evaluating crippling
strength of webs with partial-depth stiffeners.
Although Chapter J of the 2010 AISC Specification has
formulas for predicting strength of unstiffened webs and
stiffened webs with full-depth stiffeners under local compressive
loads, it does not have any formula to predict crippling
strength of webs with partial-depth stiffeners under
local compressive loads. Research on the behavior and
design rules of intermediate transverse stiffeners attached
on web panels was summarized by Lee et al. (2002, 2003).
Research on the requirements of transverse stiffeners in
straight and horizontally curved steel I-girders was summarized
by Kim et al. (2007). Research on unstiffened webs
under compressive edge loads was summarized by Elgaaly
(1983). Research on the same topic post-1983 was summarized
by Salkar (1992) at the University of Maine.
This paper highlights part of the research at the University
of Maine and gives recommendations based on the results of
this research. This paper also presents a brief comparison of
provisions of the 2010 AISC Specification, Canadian codes
(CSA, 2006) and Australian (AS, 2012) codes with respect
to crippling strength of stiffened webs under local compressive
loads.
This paper addresses the strength of stiffened webs of
rolled shapes under local compressive patch loads between
supports. Three types of local compressive patch loading
have been considered:
1. Loading through roller on top flange as shown in
Figure 1.
2. Loading through patch plate on top flange as shown in
Figure 2.
3. Loading through I-shaped beam on top flange as
shown in Figure 3.
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