STRUCTURAL ENGINEERS ASSOCIATION OF NORTHERN CALIFORNIA Continuing Education Committee Spring Seminar Series, March 14, 2012 San Francisco, California

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1 STRUCTURAL ENGNEERS ASSOCATON OF NORTHERN CALFORNA Continuing Eduation Committee Spring Seminar Serie, arh 14, 01 San Franio, California Reviion to Tilt-Up Conete Building Deign: The baktory behind hange enompaed in 009 nternational Building Code John Lawon SE California Polytehni State Univerity, San Lui Obipo (Author Note: Signifiant portion of thi paper were previouly preented at the 010 Tilt-Up Conete Aoiation Annual Convention; Lawon, 010.) Abtrat The 009 nternational Building Code (BC) ha in it ope ome ignifiant reviion that greatly affet the deign of tilt-up onete building, but to the lay engineer it appear that ome of thee proviion are a tep bakward. With the BC referening tandard inluding AC (onete) and the 008 NDS SDPWS (timber), thee doument have ignifiant hange that beome effetive with the adoption of the BC. We a engineer expet building ode to advane the tate of the art with eah ueive edition. The 009 nternational Building Code (BC) and the Building Code Requirement for Strutural Conete (AC 18-08) have ignifiant reviion affeting the deign of tilt-up building, but in ome ae not neearily advaning the tate of the art. For example, the latet AC 18 edition i largely reviing lender wall deign bak to math equation found in the old 1997 UBC. n addition, the latet BC edition i arving out an exeption to an epeially troubleome ode proviion due to an overight in the adoption proe. Other hange in timber deign are motly adminitrative or inorporating errata from the lat ode yle. Thi paper provide the bakground for thee hange and review their impat to tilt-up onete building deign and wall panel deign. n addition, a hitorial ontext i provided where if may provide ome larity. Reviion to the aked moment of inertia ( ) Sine the original inorporation of lender wall proviion into the Uniform Building Code (UBC), the atual teel area were allowed to effetively ineae in the alulation to reflet the impat of vertial ompreion load. Thi effetive teel area refleted the pretreing effet of ompreion load on the etion by onverting the ompreion fore into and effetive teel reinforing area for flexural deign. The following equation illutrate the approah urrently in AC 18-05: u lw = A + ( d ) + E f y Thi equation approah i to take the applied vertial ompreion load in the wall, aumed at the wall enter line, and ineae the teel area artifiially through the term P u /f y. Beaue the teel loation wa aumed to be typially at the wall enter line, thi i a rational approah. The aked moment of inertia i ueful in omputing a lender onete wall ultimate moment inluding eondary effet through the following AC equation. u E = 1 P 5P ua ul ( 0. 75) 48E Unfortunately, thi approah i not rational when the reinforing teel i not aligned with the reultant ompreive fore loation. Thi ituation mot frequently our in wall with two urtain of reinforing teel. Thi error ha now been orreted with a new term added to the aked moment of inertia equation provided in the AC Setion 14.8 ode proviion. Uing a new term h/d in AC equation 14-7, the effetive teel area i made rational again for either ingle or double urtain reinforing ondition. h d E Pu lw = A + ( d ) + E f y 1

2 The impat of thi ode reviion will be that flexural deign of double urtain wall will be lightly more retritive. inimum Reinforing Around Wall Opening A long tanding ode requirement ha been that onete wall opening have a minimum of two #5 reinforing bar around their perimeter. For ingle urtain wall, thi proviion ha been revied to a minimum of one #5 reinforing bar around the opening in AC Setion n addition, the minimum extenion of thee bar pat the edge of the opening ha traditionally been 4-inhe, an arbitrary length. n a more rational approah, thi ode requirement ha been lengthened to the development of F y in the bar. The impat of thi i likely minimal in California or other eimially ative tate where reinforing i typially muh larger than the minimum vertially. Slender Wall Servieability Proviion The mot ignifiant ode hange affeting tilt-up wall deign are the hange to the lender wall deign in AC Setion Thi ode etion ontain the deign proviion for lender wall deign loaded out-of-plane. To protet lender wall from experiening permanent deformation under frequent ervie-level load, a defletion equation and limitation i provided. n order to better appreiate the hange in the AC proviion, a brief hitorial diuion i provided. Thikne (inhe) Table 1 Conete Panel Data h/t Ratio Reinforing Ratio ρ (%) A viible in Figure 1, the load-defletion urve wa eentially bilinear for all panel. The wall behaved elatially until approximately two-third of the traditional modulu of rupture wa reahed (5 f ) and the initial ak formed. A the lateral load wa ineaed, additional flexural aking ourred, and the defletion rapidly ineaed. Figure 1 how the load-defletion harateriti of four of the tet panel. The defletion and load wa ineaed until failure or an extreme defletion wa reahed. Reult of the full-ale tet howed that there wa no lateral intability from the ombined lateral and eentri vertial loading. n late 1979, the Southern California Chapter of the Amerian Conete ntitute in onjuntion with the Strutural Engineer Aoiation of Southern California embarked on a landmark teting program of onete and maonry lender wall. The main goal wa to tet full ale lender onete and maonry wall that exeeded the ode limitation at the time in term of height-to-thikne ratio. Both the onete and maonry wall panel were ubjeted to a ombine eentri vertial load and lateral load to imulate gravity load and wind or earthquake lateral fore. An air bag loading apparatu with intrumentation wa utilized to load twelve tilt-up wall panel ao their four-foot width and 4-foot height. There were four different wall thiknee, and all were reinfored with four #4 vertial reinforing bar. The variou harateriti of the teted panel are in Table 1. Fig. 1 Tet Panel Load Defletion Charateriti After the teting program wa ompleted, the Tak Committee worked on odifying of the data and writing of a report that beame better known a the Green Book [AC- SEAOSC, 198]. The Committee onluded that deign of lender wall panel required not only adequate trength and afety to reit vertial and lateral load but alo a new onept to addre tiffne onern. The ervieability proviion in the urrent ode are a diret outgrowth of thi teting program.

3 A rebound tudy wa onduted during the teting program and it wa determined that L/100 wa an appropriate limit to ervie level defletion. Thi limitation wa later revied to L/150 under the UBC when it wa inorporated in the 1987 upplement to the UBC. The defletion limitation wa the firt time that ervieability wa even onidered and written into the building ode for wall panel [Amrhein, 007]. The UBC new lender wall deign method inorporated the ombined load effet due to eentri axial load and the P- effet. Strength requirement were onidered when eleting the amount of reinforement. Defletion under ervie load wa etablihed to give a reaonable limitation on the tiffne of the wall panel. The UBC lender wall proviion ontinued under thi philoophy with little hange from it introdution in 1987 until the 1997 UBC. n the late 1990 with the puh to develop a uniform national building ode, the UBC lender wall proviion were inorporated into AC Of the other two regional ode, the BOCA and SBC, no other ompeting proviion exited etting the tage for a mooth tranition of the lender wall deign philoophy. However, wherea the equation for determining the deign moment remained eentially the ame, the ervie level defletion equation were ignifiantly altered by AC during thi tranition to AC 18. Thee revied equation remain in AC 18-05, Setion and are given a: 5l Δ = 48E e a = 5P l 1 48E where: e a = aximum applied moment due to ervie load, not inluding PΔ effet; and P = Unfatored axial load at the deign (midheight) etion inluding effet of elf-weight. When omparing the UBC approah with the new AC approah, the mot ignifiant differene wa AC ue of Branon equation for e to aount for the moment of inertia redution due to aking. The previou UBC approah and SEAOSC philoophy ued a bilinear loaddefletion equation to determine the defletion. Another ignifiant hange wa the value for ued in Branon equation wa et at the traditional AC value of 7.5 f intead of SEAOSC reommended 5 f. Within SEAOSC there wa onern that the fundamental equation developed from their full-ale teting program had been ignifiantly altered by AC 18. n addition, the AC 18 ommentary ontinued to referene SEAOSC experimental reearh partially a the bai for thee new equation. n repone, SEAOSC formed a Slender Wall Tak Group in 005 to ondut a omprehenive review of the original 1981 tet data and determine the validity of the urrent UBC and new AC approahe. The SEAOSC Tak Group found that the UBC methodology mathed well with the full-ale tet data olleted in the However, the Tak Group found that the AC methodology wa a poor math for the oberved tiffne of the full-ale tet data. ore peifially, the new AC 18 equation ignifiantly underetimated the onet of aking f r and and ignifiantly underetimated the panel tiffne after aking Δ. Figure dramatially depit the large diparity between the two approahe. = aximum moment due to ervie load, inluding PΔ effet; e = a g + 1 a e = Effetive moment of inertia for omputation of defletion (alo known a Branon Equation); r (. f ) = Sf = S 7 5 ; moment at initial aking g AC UBC Tet S = Setion modulu of the gro onete etion; Fig. AC and UBC Comparion to Tet Data

4 Panel No. (1) () Table Comparion () () AC Thikne oberved UBC (in) (ft-kip) (ft-kip) (ft-kip) (1) Panel number orrepond to full-ale teting program by SEAOSC/SCCAC. All panel are 4-feet tall, 4-feet wide and reinfored with four #4 rebar. () Craking moment etimated from Load-Defletion tet data. () Craking moment alulated uing atual etion and material propertie meaured for eah peimen The Tak Group iued their opinion in a report [SEAOSC 006] and reommended that original SEAOSC methodology, whih wa inorporated into the UBC, be odified again at the national level. The two author of thi paper worked toward CC or AC adoption of the pat UBC methodology baed on their Tak Group finding. n 006, the AC 18 ommittee wa very reeptive the Tak Group finding and inorporated the neeary hange into the AC edition. The lender wall proviion of AC no longer ontain Branon formula for omputing the effetive moment of inertia, and have ubtituted in it plae a bilinear equation imilar to the UBC approah. Δ 0.67 = 0.67Δ + ( Δ n 0.67Δ ), n 0.67 One tandout differene i AC ue of 0.67Δ and 0.67 intead of the UBC Δ and. Δ and in the AC equation for Δ are till baed on the higher modulu of rupture f r for onete traditionally ued in AC 18. The 0.67 fator i imply AC approah to retifying the diparity between UBC f r = 5 f baed on tet data and AC f r = 7.5 f utomary equation. ntead of reviing AC modulu of rupture equation to reflet the tet data of initial aking, AC took the approah to imply ratio the affeted attribute Δ and (5/7.5 = 0.67). The new equation produe moment-defletion urve that are nearly idential to the UBC reult and loely math the tet data. A Table 1 and illutrate, the new equation provide onervative reult when ompared with data from the twelve tilt-up wall panel tet in the Thi ontrat harply to the non-onervative reult of AC and before. Further omparing the tet data in Table, the equation for urrently in AC overetimate the wall aking moment by 6% on average. Beaue of the drati hange in the bilinear load-defletion urve at, thi overetimation reult in a ignifiant error in alulated panel defletion. n ontrat, the UBC and propoed AC reviion onervatively underetimate by 16% on average. Table ompare the load-defletion auray of the two method with the twelve tilt-up wall panel tet. The ating moment are tabulated for a reulting defletion of 1/150 of the height of the panel. The inauraie of and Branon e ombine to aue the AC reult to ignifiantly overetimate of orreponding moment. The AC approah overetimated the ating moment by 77% on average. By omparion, the UBC and propoed AC reviion onitently provided a loe, onervative moment approximation, within 1% on average. The omparion depited in Table 1 and make lear omething ha gone atray when applying fundamental AC equation to thee lender onete wall. Neither the SEAOSC Yellow Book, the Green Book, nor the SEAOSC Slender Wall Tak Group report diu any theorie behind the lower aking moment or the empirially derived bilinear moment-defletion equation. Poible anwer lie in reearh onduted in the United State, Autralia and Canada. Autralian reearh [Gilbert, 1999] built upon the work of Andrew Sanlon and onfirmed internal onete hrinkage tree a a ignifiant fator affeting baed on flat lab defletion tet data. Normally, beam peimen ued to determine modulu of rupture f r are unreinfored and have little internal retraint, allowing free hrinkage. One reinforement i added, hrinkage i partially retrained a the reinforement goe into ompreion, auing tenile tree to develop in the onete. Thee internal tenile tree aue reinfored member to ak earlier than expeted. 4

5 Panel No. (1) () L/150 oberved () L/150 UBC UBC error () L/150 AC AC error (ft-kip) (ft-kip) % (ft-kip) % % % % % % % % % % % % % % % % % % % % % % % % % Average = -1% Average = 77% Table L/150 Comparion (1) Panel number orrepond to full-ale teting program by SEAOSC/SCCAC. All panel are 4-feet tall, 4-feet wide and reinfored with four #4 rebar. () Ating oment at Δ=L/150 etimated from Load-Defletion tet data. () Ating oment at Δ=L/150 alulated uing atual etion and material propertie meaured for eah peimen. The following equation for that predit a redued urfae tre at the initiation of aking wa adopted in 000 by the Autralian Standard for Conete Struture AS600 [Gilbert, 001]. n addition to hrinkage, the Autralian Code equation for alo inlude a proviion for axial load tree applied to the onete member. (in.-lb unit, (S unit, where: = S( 7.5 f f + P A) Pe f in pi) = S( 0.6 f f + P A) f f in Pa) 1.5ρ = ρ E ρ = A /bd ε h Pe ε h = final hrinkage train of the onete. The term P/A aount for the benefit of ompreion tree or the detriment of tenile tree on influening the aking moment. Alo, any indued tenile tree from an eentri axial load P are onidered. Thi make the AS600 equation far more omprehenive, whih i epeially important for lightly reinfored or entrally reinfored member. Reent reearh though ha onluded that the ue of / i impler and quite appropriate for omputing defletion, in lieu of the Autralian Code method [Sanlon, 008]. Thi value for mathe the 1997 UBC, whih ue: f r = 5 f (pi) or At the onet of aking, member with a entral layer of reinforement (or lightly reinfored) will have an abrupt deeae in tiffne. Beaue the internal reinforement lower the aking moment due to hrinkage, ignoring thi redution will ignifiantly overetimate the member tiffne and thu under predit the defletion. A an example, Panel #7 of the full-ale teting program wa analyzed uing AS600. The AS600 equation for predit a aking moment of 8.9 ft-kip ompared with 9.1 5

6 ft-kip oberved during the tet. A an be een in Table, the AS600 equation produe the loet etimate of for thi tet peimen ompared with the 1997 UBC and AC approahe. Reearh [Bihoff, 007] ha alo identified ignifiant limitation with Branon equation for e when applied to thin onete member with a entral layer of teel. Branon Equation, firt publihed in 1965, wa baed on larger tet beam with a ratio of gro/aked moment of inertia ( g / ) et at.. When thi ratio exeed a value of about three ( g / > ), the ue of Branon equation lead to poor predition of defletion. Slender onete wall are far above thi limit, with ommon g / ratio ranging from 15 to 5 for ingle-layer reinfored wall and 6 to 1 for doublelayer reinfored wall; thu defletion i ignifiantly under predited. The main ulprit for thi under predition i the lak of proper onideration for tenion tiffening in Branon Equation. Reommendation to replae Branon equation with a more aurate equation inorporating tenion tiffening effet imilar to the Euroode have been propoed reently [Bihoff, 007; Gilbert, 007; Lawon, 007]. Servie Level Load What are they? Thu far, thi paper ha been fouing on our ability to aurately predit the lender wall behavior, epeially defletion under ervie level load. While we may be getting more aurate in omputing the repone of thee panel, there till i a great deal of unertainty a to what ervie load atually are. Hitorially, ervie level load were imply unfatored allowable tre loading. Under the older Uniform Building Code, wind and eimi lateral load were omputed at an allowable tre level and fatored up for trength baed deign. With the tranition in the profeion heading toward trength baed deign ao all material group, eimi loading are now omputed at the trength level and mut be fatored downward for allowable tre deign. Currently, both wind and eimi load ombination involve load fator to adjut to allowable tre level and preumably ervie level loading, thu ervie level load are no longer unfatored load. t i helpful to diu at thi point the intent of ervie level loading hek. With the ineaing awarene of performane baed deign onept, the intention of ervie level hek are to enure a higher level of performane under lower, but more frequent, level of earthquake or wind fore. n lender wall deign, uffiient panel tiffne i onidered important to prevent permanent deformation under maller earthquake or wind that may our frequently. nteretingly, ASCE 7-05 ontain Appendix C whih i a helpful beginning to undertanding ervie level loading. Appendix C explain the intent of ervie level loading i to addre frequent event that have a 5% probability of being exeeded annually. Appendix C wind load ombination i given a: D + 0.5L + 0.7W Compared to pat allowable tre load ombination, thi provide a lower deign iteria, but no longer baed on an arbitrary methodology without probability. Thi ame 0.7W fatored wind load an alo be found in 006 BC Table 1604., footnote f, for wall deign. Note: Appendix C wa omitted in the firt printing of ASCE 7-05 but beame available a errata. Unfortunately, ASCE 7-05 doe not provide a diuion on developing a imilar load ombination for eimi deign. Trying to develop a imple load ombination for eimi with the intent of a 5% annual probability of exeedene i not poible due to the different approahe taken for rik expoure ao the United State. The deign petral aeleration inorporated into the building ode are not baed on a uniform probability, but intead have been modified for different region of the United State. The eatern part of the ountry i largely baed on a probability methodology while the wetern oat i primarily baed on a determiniti methodology. Here in California, the determiniti approah prevail and i not aoiated with how frequent peifi ground motion our, but intead how large an earthquake an a peifi fault generate. Thi lak of uniformity between eat and wet region of the United State, and the lak of a uniform probability approah in California for ground motion, reult in the inability to apply a imple one-ize-fit-all load fator for ervie load. Subequently, AC ommentary Setion R for alternate lender wall deign reommend imply applying the following load ombination for ervie level eimi loading: D + 0.5L + 0.7E Thi load ombination i realitially a tep bak in time to our old allowable tre fore level whih traditionally have been ued without a problem. t hould be pointed out that in low eimi region of the United State, the 0.7E greatly overetimate the expeted fore level aoiated with 5% annual probability, and there may be ome merit in the 6

7 itiim that thi fore level i too onervative in area of low to moderate eimi rik. Thi i an area that ould benefit from further reearh. Dutility Proviion for Wall Anhorage n Seimi Deign Category C and higher, AC Appendix D require anhorage to onete to be deigned to behave in a dutile manner. The engineer ha another option allowed by the 006 BC to deign the onnetion for.5 time more fore in lieu of atifying dutility. A will be now diued, thi approah unfortunately failed to reognize the intent of the wall anhorage fore inorporated into the 006 BC. The 006 BC wall anhor fore are eentially the ame a thoe found in the previou 1997 UBC. Firt, a little bakground i neeary. Following the 1994 Northridge earthquake, urvey of damage to onete and maonry building with flexible roof diaphragm revealed that very limited amount of wall anhorage dutility were preent to reit the indued fore. Brittle tenile failure in teel wall anhorage trap were epeially troubleome. n addition, boundary nailing in plywood diaphragm tore out of the plywood edge due to wall anhorage elongation. New ode proviion were introdued into the 1997 UBC to addre the nondutile wall anhorage behavior oberved in the Northridge earthquake UBC Setion wa hiefly written to addre many of the wall anhorage iue potlighted in the Northridge earthquake. The lak of oberved dutility and the need for greater anhorage trength were the reaon behind 1997 UBC Setion tem 1 and 4. Wall anhorage fore to flexible diaphragm in Seimi Zone & 4 were ineaed 50% (a p =1.5) and teel element had an additional 1.4 fore multiplier. The intent of Setion (item 1, 4, and 5) wa for the wall anhorage ytem to reit brittle failure when ubjeted to maximum expeted roof aeleration. Baed on obervation of Northridge earthquake damage, it wa deemed bet to reit brittle failure through the ue of ignifiantly higher deign fore in onjuntion with antiipated material overtrength intead of any reliane on dutility. A a reult, material-peifi load fator were introdued to provide a uniform level of protetion againt brittle failure (1.4 teel, 0.85 wood, 1.0 onete/maonry). Thi approah i well doumented in the 1999 SEAOC Reommended Lateral Fore Requirement and Commentary (The Blue Book) [Referene C ]. A further evidene of the intent of thee wall anhorage proviion, the 1999 SEAOC Blue Book Commentary tate that the redued R p value for nondutile and hallow anhorage doe not apply to wall anhorage deigned uing thi overtrength approah of Setion [Referene C ]. n the development of ASCE 7-05, the intent wa to maintain the ame wall anhorage equation between the 1997 UBC and ASCE 7-05 for flexible diaphragm in high eimi zone. The wall anhorage proviion of ASCE 7-05 Setion are diretly inorporated from the 1997 UBC Setion Subtituting C a = 0.4S DS (00 NEHRP Commentary), it an be onfirmed that Eq i generally equivalent to the 1997 UBC. Through an unrelated parallel effort, AC Appendix D Setion D...4 and D...5 require anhorage dutility in moderate and high eimi zone. AC dutility requirement onflit with the intent behind Setion at wall anhorage ituation. Furthermore, 006 BC Setion allow an additional.5 load fator on top of ASCE fore in lieu of the AC dutility requirement. Thi taking of load fator on top of load fator and dutility requirement i in onflit with the original intent of the wall anhorage proviion. To ummarize, the 1997 UBC and ubequent ASCE 7-05 implement very high wall anhorage fore level to ahieve uniform protetion againt brittle failure without reliane upon dutility. Thi wa ahieved uing a rational approah onidering inherent overtrength. Through the inorporation of AC 18 Appendix D, anhorage dutility requirement were inadvertently added to thee peial wall anhorage ituation in onflit with the original intent of the proviion. Furthermore, the 006 BC fore multiplier of.5 i redundant to the original fore ineae behind the UBC and ASCE wall anhorage proviion. Ahieving anhorage dutility under AC 18 Appendix D i very diffiult for tilt-up ontrution with flexible diaphragm. For the dutility ondition to be met, teel anhor trength mut be weaker than the onete breakout trength. Beaue tilt-up wall are inherently thin lender wall deign, anhor embedment depth i limited, making it diffiult to ineae. n everal parametri tudie, it i apparent that the dutility proviion enourage maller diameter teel anhor or thiker onete wall for deeper embedment. Neither of thee approahe eem benefiial. Another unintended onequene of providing dutile anhorage i the potential elongation of the teel auing boundary nailing at plywood diaphragm to tear out of the heathing edge under maximum eimi fore level. Similar onern exit for edge welding along teel dek diaphragm at the wall panel. 7

8 Uing the 006 BC alternative, the fore are ineaed to an extreme level due to the.5-time load ineae previouly mentioned. n everal parametri tudie, thi reult in a larger number of thin anhor rod pread out over a larger onnetion area. Spreading thee anhor rod out likely reult in non-uniform anhorage fore ditribution, and intead onentrate the fore over the loet few rod, potentially reulting in a progreive rod failure. Reognizing the onflit within the building ode, the nternational Code Counil aepted a propoed BC ode reviion from thi author at the Final Ation Hearing in inneapoli, inneota in September 008. Thi ode reviion eate an exeption to the requirement for dutility or the.5 time overtrength proviion when the deign fore are omputed uing wall anhorage proviion at flexible diaphragm. The following tatement now i ontained in the 009 BC Setion : Anhor deigned to reit wall out-ofplane fore with deign trength equal to or greater than the fore determined in aordane with ASCE 7 Equation or need not atify Setion D...4 [nor] D...5. the author reommendation to fou on taple a a olution only when onidering repair option in the field to minimize plitting. Conluion The inevitable hange that our between ode yle often leave engineer bewildered a to the reaon behind the new proviion. n a general ene, we expet building ode to evolve a new knowledge i gained from iene and experiene. The hope i that we further the tate-of-the-art and provide afer, more effiient, building with eah ode yle. Oaionally, ode proviion are eated in a hurry without the neeary perpetive to inure intent i honored. With thi ode yle, tilt-up ontrution tate of the art i being advaned in ome intane and being returned appropriately to the pat in other. The proe of building ode development involve many volunteer who purue rational ode proviion that puh the tate of the art forward for afer and better truture. While not infallible, thoe who work toward thi goal hould be ommended. Reviion to Wood Sheathed Diaphragm With the BC oordination with and inorporation of the 008 NDS Seimi Deign Proviion for Wind and Seimi (SDPWS), everal hange affet tilt-up onete building with wood diaphragm. When diaphragm hear fore exeed 80 lb/ft (ASD), the traditional diaphragm hear table i inuffiient and the deigner mut eek deign olution from the High-Load Diaphragm table in the 009 BC, and i now alo in the 008 SDPWS. The 006 BC had inorporated the high-diaphragm onept from APA evaluation report CC-ES 195, but inadvertently omitted the important nail paing and tagger diagram from the report. Thi omiion left onfuion among deigner who had never onulted the original evaluation report that the table wa baed on. n the new 009 BC, thi omiion ha been retified and the diagram are now inluded. n an effort to further onolidate wood framing proviion into the NDS publiation, the 009 BC ha removed the proviion and equation for diaphragm defletion utilizing nailing, and intead i deferring to the SDPWS where the ame proviion are tated. One exeption i that the defletion of diaphragm utilizing taple i till in the 009 BC, however taple are not very ommonly ued, and it i Fig. The SCCAC / SEAOSC Green Book Team Referene AC-SEAOSC, 198, Tet Report on Slender Wall, By the AC-SEAOSC Tak Committee on Slender Wall, Strutural Engineer Aoiation of Southern California, Whittier, CA. Amrhein, 007, Wall, Wall, Wall, Wall, By Jame Amrhein and Jame Lai, STRUCTURE agazine, NCSEA, Chiago, L, July,

9 Bihoff, 007, Effetive oment of nertia for Calulating Defletion of Conete ember Containing Steel Reinforement and Fiber-Reinfored Polymer Reinforement. By Peter Bihoff and Andrew Sanlon. AC Strutural Journal, Amerian Conete ntitute, Farmington Hill,, January-February, 007. Gilbert, 1999, Defletion Calulation for Reinfored Conete Struture Why We Sometime Get t Wrong. By R. an Gilbert. AC Strutural Journal. Amerian Conete ntitute, Farmington Hill,, Nov-De Gilbert, 001, Defletion Calulation and Control Autralian Code Amendment and mprovement. By R. an Gilbert. Code Proviion for Defletion Control in Conete Struture SP 0-4, Amerian Conete ntitute, Farmington Hill,, 001. Gilbert, 007, Tenion Stiffening in Lightly Reinfored Conete Slab. By R. an Gilbert. Journal of Strutural Engineering, Amerian Soiety of Civil Engineer, Reton, VA, June, 007. Lawon, 007, A Call for Unified Deign Defletion Limit for Tilt-Up Wall Servieability, By John Lawon, Strutural Engineer, Zweig White, Chiago, L, January, 007 Lawon, 010, New Code Change under the 009 BC, Proeeding of the 010 TCA Annual Convention, rvine, California, September 9-Otober 1, 010. Sanlon, 008, Shrinkage Retraint and Loading Hitory Effet on Defletion of Flexural ember. By Andrew Sanlon and Peter Bihoff. AC Strutural Journal, Amerian Conete ntitute, Farmington Hill,, July- Augut, 008 SEAOSC, 1979, Reommended Tilt-up Wall Deign, Strutural Engineer Aoiation of Southern California, Whittier, CA, June, SEAOSC, 006, UBC 97 and AC 18-0 Code Comparion Summary Report, SEAOSC Slender Wall Tak Group, Strutural Engineer Aoiation of Southern California, Whittier, CA, January, 006 9