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HomeMy WebLinkAboutFile Documents.630 W Hopkins Ave.0052-2020-BRES (6) Edward C.Robison, P.E. 16 OCT 2019 C.R.Laurence Co.,Inc. 2503 East Vernon Los Angeles,CA 90058 SUBJ: CRL SRS STANDOFF RAILING SYSTEM GLASS BALUSTRADE GUARDS The SRS Standoff Railing System is a guardrail system that utilizes point supported glass balustrades. When constructed in accordance with the attached details and installation guidelines the guardrail can designed to safely support the following loading conditions: 200 pound point load on top rail,vertical or horizontal or 50 plf load on top rail,vertical or horizontal or 25 psf uniform load on glass panel horizontal or 50 lb conc load on 1 sf or Wind load -As listed with respect to glass size or determined by FEA modeling Typical glass thickness: 3/4" monolithic or 13/16" laminated minimum thickness. For exterior installations wind loads and glass stress must be calculated by a qualified licensed engineer. For single family residential construction only the 200#concentrated top rail load,50#concentrated load and wind load (exterior) are applicable (non-concurrent). The SRS is to be used with tempered glass only,laminated or monolithic. Laminated glass must be made with Kuraray SentryGlas+ interlayer or an equivalent ionoplast interlayer. Glass light stresses were evaluated using finite element analysis (FEA) with SCIA Engineer 18.1 in order to derive rules for designing a code compliant system. Generally,a qualified licensed engineer must evaluate a specific installation for code compliance using a FEA model or other recognized method. All results given in this paper are based on the assumption that the top rail has inadequate strength and stiffness to cause significant load sharing between the glass lights except as specifically stated herein. Added support from stronger and stiffer top rails that anchor to posts or walls independent of the glass balustrade may significantly reduce the glass stresses and deflections. When designing a glass balustrade with the additional support a FEA model should be used which accounts for the proposed specific conditions. The recommendations herein are intended to assist a qualified licensed engineer in developing a code compliant guard that meets the applicable requirements of the 2009,2012,2015 and 2018 International Building Code and state codes adopted from the IBC codes. This paper is not intended to demonstrate the code compliance of an installation but is to only be utilized by the qualified 10012 Creviston DR NW 253-858-0855 Gig Harbor,WA 98335 fax 253-858-085��^���V/�(� �A email: elrobison@narrows.co ,.� 10/19/2020 ASPEN BUILDING DEPARTMENT CR Laurence Standoff Rail System — SRS 10/16/2019 Page 2 of 31 licensed engineer in charge of the glass balustrade guard in analyzing the glass stresses and anchorage. This paper only evaluated 2 and 3 standoff pairs per light. Additional standoffs may be used and will decrease the glass stress. If additional standoffs are proposed a FEA model should be used to determine the glass stresses,deflections and standoff reactions. Notes on developing an effective FEA model: When developing a FEA model the glass stresses are very sensitive to small changes in the boundary conditions and how the supports are represented. It should be assumed that the clamping at the standoff fittings when using the fittings in this paper will provide reaction points at the horizontal centerline of the edges of the holes. No significant moment resistance will occur at the standoffs so that the reactions should be modeled as surface bearing only. Moment resistance is provided by the force couple developed between the two standoffs in a pair. These recommendations are based on creating a FEA model that is consistent with the results of physical testing by CRL The standoffs must always be used in vertical pairs. Vertical loads should be assumed as acting on only a single standoff in each pair,and only on two standoffs when more than 2 pairs are used. Table of Contents Signature Page 3 Glass Strength 4 - 5 Glass Panel Loads 5 Allowable Wind Loads 6 - 13 Guard Rail Applications 14 - 15 Glass Standoffs 16— 17 Custom Standoff lengths 18 RSOB20 Fitting 19 Grab Rails and Cap rails 20 FEA Result Tables 1/2" glass 21 - 31 Edward Robison,P.E. Edward C.Robison,P.E. 10012 Creviston DR NW 25 a Gig Harbor,WA98335 fax 2' - ��� email: elrobison@na 10%.co/2020 ASPEN BUILDING DEPARTMENT CR Laurence Standoff Rail System—SRS 10/16/2019 Page 3 of 31 0..c0\F sC A i-, j OQ�OFE 'we ••��,•o�PD°•L/c•�'�-� �P�Q C Roe/S F � k, O O F ,.• .. •o c.'Ro s-: C N cc �,Y�� 42123 0�� �P� �i�p2t ?°;�eQ ;a �� ,� E SF �Z EDWARD C. w © .C 65883 z �� 54027 = L�63683 _t n No o '/ , .���' 0 �<v A IF 14 'at o ry A S'P ` q� \��P�� ','�� .......... . .• . �SS�ONAL E��� EXP 03 1/2020 �F CAS EXP 02/28/2021 011111/0 P C. ROBi \�.\\c°F.C A R••)•//, ( FE Z = ;•O '.O. * ENGINEER * .:EDWARD C.•:GI - I Z: No. 11576-S ow ; ROBISON • m 7- ..,�;,y'tl1�I�� 11,"6i ' ...t.„,:: ,..„,../c-:". '.0: 107171.,„;,' THIS WORK WAS PREPARED BY UNDER MY SUPERVISION OF �•y'S•t �iSi�NALk k•\\ /" Professional Certification.i hereby certify that these /30/2020 EXP 11/30/2020 documents wcrc prepared or approved bymc,and that I am a duly licensed professional engineer under the laws of the State of Maryland, Signature Expiration Date of the License \\ License No.52500,Expiration Date:04/092020 ......r.... „,: \\�� . I rr EDWARD C. �..5,, Ss�•s f.-,.• EDWARD C.':•0 ►i Edwar. C Ro� ert •Q:•., ENGINEER O''•01 0; ROBISON :p Ii . - ROBISON • Z'z 1 (n, 1 2/31/2019: 91 lip �', .. 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Gig Harbor,WA 98335 fax 2'I L.: t :.- ;�VED email: elrobison@na 10 flQ /2020 ASPEN BUILDING DEPARTMENT