1、SEI /ASCE 23-97 American Society of Civil Engineers Specification for Structural Steel Beams with Web Openings This document uses both Systme International (SI) units and customary units. Structura/ Engineering Institute SEIIASCE 23-97 Structural Engineering Institute American Society of Civil Engin
2、eers Specification for Structural Steel Beams with Web Openings This document uses both Systeme International (SI) units and customary units. Structural Engineering Institute Published by the American Society of Civil Engineers 1801 Alexander Bell Drive Reston, Virginia 201 91 -4400 ABSTRACT This Sp
3、ecification covers the design of composite and non- composite beams with web openings. Basic design proce- dures involve determination of maximum nominal flexural ca- pacity, maximum nominal shear capacity, and interaction of flexure and shear. Section properties are limited to ensure ductile behavi
4、or. Rectangular and circular openings, with or without opening reinforcement, are addressed. The specifi- cation follows load and resistance factor design philosophy. Library of Congress Cataloging-in-Publication Data Specification for structural steel beams with web openings / American Societv of C
5、ivil Enaineers. p. cm. - (ASCE standah) “SEI/ASCE 23-97.” ISBN 0-7844-0300-7 Includes bibliographical references. 1. Girders-Specifications-United States. 2. Buildinq, Iron and steel: 3. Composite construction. 4. Load factor design. 1. American Society of Civil Engineers. II. Series: American Socie
6、ty of Civil Engineers. ASCE Standard. TA66O.B4 S64 1998 624.1 7723 -dc2 1 98-41 258 CIP r98 Photocopies. Authorization to photocopy material for internal or personal use under circumstances not falling within the fair use provisions of the Copyright Act is granted by ASCE to libraries and other user
7、s registered with the Copyright Clear- ance Center (CCC) Transactional Reporting Service, pro- vided that the base fee of $8.00 per article plus $SO per pa e is paid directly to CCC, 222 Rosewood Drive, Danvers, $A O1 923. The identification for ASCE Books is O-7844-0300-7/ 99/$8.00 + $.50 per page.
8、 Requests for special permission or bulk copyin should be addressed to Permissions 13 Copy- right Dept., ASCE. Copyright O 1999 b the American Society of Civil Engineers, All Rights Resewed: Library of Congress Catalog Card No: 98-41258 Manufactured in the United States of America. ISBN 0-7844-0300-
9、7 In April 1980, the Board of Direction approved ASCE Rules for Standards Committees to govern the writing and maintenance of standards developed by the Society. All such standards are developed by a consensus standards process managed by the Man- agement Group F (MGF), Codes and Standards. The cons
10、ensus process includes balloting by the balanced standards committee made up of Society members and nonmembers, balloting by the membership of ASCE as a whole, and balloting by the public. All standards are updated or reaffirmed by the same pro- cess at intervals not exceeding 5 years. The following
11、 Standards have been issued. ANSUASCE 1-82 N-725 Guideline for Design and Analysis of Nuclear Safety Related Earth Structures ANSUASCE 2-9 1 Measurement of Oxygen Transfer in Clean Water ANSUASCE 3-91 Standard for the Structural Design of Composite Slabs and ANSUASCE 9-91 Stan- dard Practice for the
12、 Construction and Inspection of Composite Slabs clear Structures (ACI530-95/ASCE5-95/TMS402-95) and Specifi- cations for Masonry Structures (AC1530.1-951 ANSUASCE 7-95 Minimum Design Loads for Build- ANSE 4-86 Seismic Analysis of Safety-Related Nu- Building Code Requirements for Masonry Structures A
13、SCE6-95mMS602-95) ings and Other Structures ANSUASCE 8-90 Standard Specification for the De- sign of Cold-Formed Stainless Steel Structural Members ANSUASCE 9-91 listed with ASCE 3-91 ANSUASCE 10-97 Design of Latticed Steel Trans- mission Structures ANSUASCE 11-90 Guideline for Structural Condi- tio
14、n Assessment of Existing Buildings ANSVASCE 12-91 Guideline for the Design of Ur- ban Subsurface Drainage ASCE 13-93 Standard Guidelines for Installation of Urban Subsurface Drainage ASCE 14-93 Standard Guidelines for Operation and Maintenance of Urban Subsurface Drainage ANSUASCE 15-93 Standard Pra
15、ctice for Direct De- sign of Buried Precast Concrete Pipe Using Stan- dard Installations (SIDD) tor Design (LRFD) of Engineered Wood Construction ASCE 16-95 Standard for Load and Resistance Fac- ASCE 17-96 Air-Supported Structures ASCE 18-96 Standard Guidelines for In-Process ASCE 19-96 Structural A
16、pplications of Steel Cables ASCE 20-96 Standard Guidelines for the Design and ASCE 21-96 Automated People Mover Standards- ASCE 22-97 Independent Project Peer Review ASCE 23-97 Specification for Structural Steel Beams Oxygen Transfer Testing for Buildings Installation of Pile Foundations Part I with
17、 Web Openings . 111 The material presented in this publication has been prepared in accordance with recognized engi- neenng principles. This Standard and Commentary should not be used without first securing competent advice with respect to their suitability for any given application. The publication
18、 of the material contained herein is not intended as a representation or warranty on the part of the American Society of Civil Engi- neers, or of any other person named herein, that this information is suitable for any general or particular use or promises freedom from infringement of any patent or
19、patents. Anyone making use of this infor- mation assumes all liability from such use. V The American Society of Civil Engineers (ASCE) acknowledges the work of the Structural Steel Beams with Web Openings Standards Cornmit- tee of the Codes and Standards Activities Division of the Structural Enginee
20、ring Institute of ASCE. This group comprises individuals from many backgrounds including: consulting engineering, research, construc- tion industry, education, goverment, design and pri- vate practice. This Standard was prepared through the consen- sus standards process by balloting in complince wit
21、h procedures of ASCEs Codes and Standards Activities Committee. This Specification and accompanying Commen- tary cover the design of composite and noncomposite beams with web openings. The specification is writ- ten for structural designers for use with the AISC David Darwin, Chairman University of
22、Kansas W. Samuel Easterling, Secretary Virginia Polytechnic Institute occurs when Vu = O V, = Maximum nominal shear capacity at opening; occurs when Mu = O at opening centerline use a, used to calculate v in Eq. (2), only when opening is reinforced and (G + p)/(v + fi) 5 1 A, = Cross-sectional area
23、of web reinforcement along top or bottom edge of opening b, = Width of flange = Dimensionless ratio relating the secondary bending moment contributions of concrete and opening reinforcement to the product of the plastic shear capacity of a tee and the depth of the tee, P, = Force in reinforcement al
24、ong one edge of opening = FyA, 5 Fytwa0/(2d), I Fy(Af + Ajr) d, = Distance from outside edge of flange to centroid of reinforcement ends of opening, respectively; for top tees in composite sections only d, di = Distances from outside edge of top flange to centroid of concrete force at high and low m
25、oment ends of opening, respectively; for top tees in composite sections only. Pch, Pcr = Concrete forces at high and low moment A, = Area of flange = bft,. A, = Area of flange cover plate reinforcement t, = Thickness of flange 4.3.2 Top Tee in Composite Beams The force in the concrete at the high mo
26、ment end of the opening Pch shall be calculated using the minimum value obtained from Eqs. (4a) through (4). where f f = Specified concrete compressive strength be = Effective width of concrete slab N = Number of shear connectors between the high Q, = Individual shear connector capacity, including m
27、oment end of the opening and the support reduction factor for ribbed slabs i, = Effective thickness of concrete slab (=ts for solid slab; =ti for slab with ribs perpendicular to steel beam; =(ti + tJ2 for slab with ribs parallel to steel beam) t, = Total thickness of concrete slab ti = Thickness of
28、slab above the rib A, = Steel area of top tee; where reinforcement of the opening is used, the area of this reinforcement shall be included in A, b, and Qn shall be calculated in accordance with Chapter I of the American Institute of Steel Construc- tion Load and Resistance Factor Design Specijcatio
29、n for Structural Steel Buildings. The force at the low moment end of the opening, Pel, shall be calculated using Eq. (5). where No = Number of shear connectors over the opening Only shear connectors completely within the de- fined ranges shall be considered in N or No. The dis- tances from the top o
30、f the flange to the centroids of the concrete forces at the high and low moment ends of the opening, dh and d, respectively, shall be caicu- lated using Eqs. (6) and (7). for solid slabs. pch dh = t, - 1.7 ffb, pci d, = - 1.7 f:be (7) for slabs with ribs perpendicular to steel beams. shall be based
31、on the centroid of the compressive force in the concrete considering ail ribs that lie within the effective width be; in lieu of a more pre- cise calculation, di may be calculated using Eq. (7a), replacing be by the sum of the minimum rib widths for the ribs that lie within b,. If the term (G + p)/(
32、v + fl) in Eq. (2) ex- ceeds 1.0, V, shall be calculated using Eq. (8): For slabs with ribs parallel to the steel beam, di b v, = - v, 5 v, V 2 where SEVASCE 23-97 5.2.3 For v = aJs, for both reinforced and unreinforced openings. In Eq. (8), CL shall be based on Eq. (3) using values of Pch and P, th
33、at are limited such that Pch shall not exceed the values given in Eqs. (4a), (4b), and (9). In no case shall V, for the top tee in composite beams exceed the plastic shear capacity of the top tee, V,(sh), given in Eq. (10). V,(sh) = V, + 0.29fi A, N V,(sh) = V, + O.ilfi A, kips (loa) (lob) where f:
34、and or (lob), respectively, and A, = effective concrete shear area = 3tste. are in MPa or ksi for Eqs. (loa) 5.0 DESIGN CRITERIA To design members with web openings under the provisions of this Specification, the following criteria must be satisfied. 5.1 STEEL SECTION The member must be a compact se
35、ction, under the provisions of Chapter B, American Institute of Steel Construction Load and Resistance Factor De- sign Specijication for Structural Steel Buildings. 5.2 WEB BUCKLING 5.2.1 The requirements of Sections 5.2.2, 5.2.3, and 5.2.4 shall be satisfied for openings with ho 2 0.3d, unless web
36、buckling strength is evaluated. 5.2.2 The width to thickness ratio of the web, (d - 2t,)1tw, shall not exceed 1365/*, F, in MPa, (520/*, F, in ksi). (d - 25) 1100 I- * F, MPa tW (d - 25) 420 the following limitations apply: 2- v, 5 3 v, for noncomposite beams and for composite beams in negative bend
37、ing 2- 3 v, I - v, + v, for composite beams in positive bending. For 420 d - 2tJ 520 20 at the centerline of the opening and v 4, noncompos- te tees in compression shall be designed as axially loaded columns with an effective length = a,. 5.4 LATERAL BUCKLING Noncomposite beams and negative moment r
38、egions of composite beams subject to lateral buck- ling of the compression flange shall be proportioned so that member strength is not governed by the strength at the opening, determined without regard to lateral buckling. The effect of the opening on lateral buckling of the member shall be consider
39、ed. 5.5 MAXIMUM OPENING DIMENSIONS The depth of the opening h, shall not exceed 0.7d and the length of the opening a, shall not ex- ceed lSd, where d is the depth of the steel section. 5.6 TEE PROPORTIONS 5.6.1 The depth of a tee in compression shall not be less than O. 15d. 5.6.2 The ratio of the o
40、pening length to the depth of the steel portion of a tee in compression v shall not exceed 12. 5.6.3 If the depth of a tee in tension is less than 0.15d for noncomposite beams or 0.12d for compos- ite beams, or if v is greater than 12, V, = O. Open- ings shall not extend into the toe of web-to-flang
41、e fillets. (a) the comers are drilled prior to cutting the straight portions of an opening; and (b) the straight portions of the opening are cut so that neither overruns nor notches are formed at the juncture of the straight portions and the holes. 5.8 CONCENTRATED LOADS 5.8.1 Unless a detailed anal
42、ysis is performed, no concentrated loads shall be placed at an opening. 5.8.2 Bearing stiffeners shall be required for concen- trated loads if (a) (d - 2t,)/t,. I 11OOifi and bit I 140/*, F, in MPa (d - 2t,)/tw 5 4201*y and blt 5 54/*, F, in ksi and the load is placed closer than di2 to the edge of
43、the opening; or if in MPa (d - 2t,)/t, 5 520lfi and blt I 65/fl, F, in ksi and the load is placed closer than d to the edge of the opening, where b and t are the projecting width and thickness, respec- tively, of flange or reinforcement. (b) (d - 2t,)/t, I 1365ifi and bit I 170/*, F, 5.8.3 The provi
44、sions of 5.8.1 and 5.8.2 do not apply to concentrated floor loads that are specified in build- ing codes as an alternative loading for comparison with uniform loads. 5.9 PLACEMENT OF OPENING Unless a detailed analysis is carried out, the nearest edge of the opening shall be placed no closer than a d
45、istance d to a support. 5.10 SPACING BETWEEN OPENINGS 5.7 CORNER RADII 5.7.1 The corner radii of rectangular openings shall not be less than 2tw or 16 mm (518 in.), whichever is greater, unless the provisions of Section 5.7.2 apply. 5.7.2 The corner radii of rectangular openings shall not be less th
46、an 9.5 mm (318 in.) for openings that satisfy both of the following requirements: To be treated as individual openings for design, the clear spacing S between multiple openings in both noncomposite and composite members shall sat- isfy Eqs. (1 la) through (12b). The spacing between multiple openings
47、 in composite members shall also satisfy Eqs. (13a) and (13b). Interaction between openings shall be considered in members with open- ings not meeting these criteria. 4 SEUASCE 23-97 For rectangular openings S 2 ho For circular openings S Z 1.50, V,. where Do = Diameter of opening. For composite bea
48、ms S 2 a, S 1 2.0d 5.11 CIRCULAR OPENINGS It is permissible to design members with circular openings using expressions developed for rectangular openings, using the following substitutions. For unreinforced openings: ho = Do (for bending) ho = 0.9D0 (for shear) a, = 0.450, 5.12.1 Opening reinforceme
49、nt may consist of hori- zontal web reinforcement, flange reinforcement, or both. Web reinforcement shall consist of continuously welded bars parallel to and attached as closely as practical to the edge of the opening. Flange rein- forcement shall consist of plates or bars continuously welded to either flange. (1 la) (1 lb) 5.12.2 The specified yield stress of the reinforcement shall equal or exceed the specified yield stress of the beam. (12a) 5.12.3 The weld in each extension of the reinforce- ment beyond the ends of the opening shall develop
