WASHINGTON COUNTY OREGON

Transcription

1 WASHINGTON COUNTY OREGON BUILDING SERVICES ENGINEERING PLAN REVIEW GUIDELINES (PRG 2): Guidelines Objective: 1. Imprve cmmunicatins between Building Services and the engineering design cmmunity that prepares cnstructin dcuments. 2. Imprve cnsistency and quality f engineering submittals and prject reviews. 3. T prmte bjective and a systematic apprach t the engineering plan review thrugh the use f Structural Engineering Plan Review Guidelines as a means t cmmunicate t the public. 4. T ensure that building and ther structures within Building Services a jurisdictin are structurally safe and meets r exceeds cde minimum standards. 5. T prmte fairness, curtesy, and respect within the engineering team that prmtes efficient use f Building Services limited resurces in plan review wrk. Abbreviatins used in this dcument: AOR / EOR The architect r engineer in general respnsible charge f the prject (see OSSC prvisins) BSE Building Services Engineering BE Building Engineer LBE Lead Building Engineer / Plan Review Supervisr Guideline Summary: The fllwing shuld be used by engineering plan reviewers as a guide t hw t apprach ur duties: Purpse f Engineering Plan Review T verify that prjects engineering design are in substantial cmpliance with the cde. The BE s jb is t cnduct a verificatin that the plans are in substantial cmpliance with the building cde, with the gal f prtecting the general health, safety, and welfare f the public. Character f Plan Review The permit apprval prcess shuld be a cllabrative effrt between the design prfessinal and the BE. Given the respective rles and respnsibilities f the designer and the reviewer, the prcess f ensuring a building cnfrms t the cde shuld be a cllabrative effrt between the tw. Thrugh an pen line f cmmunicatin between the design engineer and the BE. The BE shuld be aware f different levels f apprpriate cmmunicatin, based n levels f cmplexity a phne call culd be sufficient t handle easy issues, althugh written fllw up may be needed. Scpe f Review The fcus f the BE shuld be n the apprval f the cnstructin dcuments per cde. A plan reviewer s jb is t review and apprve the cnstructin dcuments fr permit issuance. Supprting dcumentatin such as structural calculatins submitted are aids t help the BE with his r her review, and are nt part f the apprved cnstructin dcuments. Structural calculatins are useful t determine if a design engineer has addressed a particular issue, but they are nt part f the cnstructin dcuments and shuld nt be reprduced n the plans. Department f Land Use & Transprtatin Develpment 1 Services Divisin Building Services Sectin

2 Level f Review It is reasnable fr the BE t require enugh infrmatin in the cnstructin dcuments r review aids t cnduct a review f the plans. What cnstitutes a reasnable engineering review will vary, depending n many factrs including: Prject scpe (e.g., a single family residence versus relatively a large cmmercial building) Structural systems cmplexity (e.g., cnventinal wd framing versus a mid-rise steel r cncrete shear wall building) Plan clarity and cmpleteness Whether r nt the plans are prepared by a registered design prfessinal versus a lay persn. It is als recgnized that the level f review shuld vary with the cmplexity f a prject. T that effect a simple single family residence des nt need the same level f review as a large cmmercial building r a schl. Engineering Judgment The BE shuld cnsider the design engineer s judgment, where there is n direct cnflict with a cde requirement. The fllwing principles represent a balance between the design engineer s and the BE respnsibilities: In general, a design engineer shuld be able t articulate his r her ratinale as t hw a particular engineering issue is addressed. It is apprpriate fr BE t ask the design engineer hw he r she arrived at his r her design. Hwever, if the design engineer is able t give a reasnable (i.e., ratinal and technically justified) explanatin, the BE shuld defer t the engineer s judgment, particularly if the issue under discussin is nt directly addressed in the cde. Design engineers respnses t issues raised by the BE shuld address the cncerns expressed and prmte a cllabrative effrt. Because I say s r Because I m an engineer and yu re nt r similar ways f aviding answers are nt reasnable nr cllabrative explanatins. BE shuld keep in mind there can be several ways f slving design issues, and if reasnably justified as described abve, deference shuld be given t a design engineer s unique slutin t a prblem (e.g., using a methd r detail that hasn t been seen befre). It is apprpriate fr a BE t ask an engineer t justify a design that directly cntradicts a cde requirement. Fr example, a reinfrced cncrete clumn that des nt have ties r spirals at the cde-required spacing shuld be questined, since ductile detailing is an imprtant design feature that helps structures t survive earthquakes. Building Engineer s Judgment The BE shuld exercise judgment in deciding which issues t address in cnducting a review. In exercising his/her judgment, hwever, the BE shuld refrain frm impsing his/her wn idea f what cnstitutes best practices n the design engineer. If a design cmplies with the cde, it shuld be apprved, regardless f whether r nt the plan reviewer wuld have designed it differently based n his r her experience. LBE Duties: Under the general directin f the Building Official the LBE shall direct the wrk f Building Services engineering staff day t day perfrmance f engineering plan review f cnstructin dcuments submitted fr permits. LBE essential duties are: 1. T prmte and be accuntable fr custmer satisfactin and quality f service thrugh the spirit f partnership. 2. Assigned prjects, rganizes and crdinates engineering plan review and field engineering changes review activities cnsistent t engineering review guidelines. Department f Land Use & Transprtatin Develpment 2 Services Divisin Building Services Sectin

3 3. Serve as facilitatr n prjects where there is a disputed cmment(s) that cannt be reslved between the BE and the A/E f Recrd. In all such cases LBE shall prvide guidance t mve the respective prjects frward t reslutin cnsistent with stated bjective abve. 4. In disputed issues amng BE s r between BE and AOR / EOR, the LBE shall make the final recmmendatin t the Building Official fr apprval. 5. Other additinal task r assignments as directed by the Building Official. A. General Engineering Plan Review Prcedure BSE is respnsible t assure that building permit engineering dcuments including drawings, calculatins and specificatins cmply with OSSC and ther Building Services regulatins. BSE rle is t d efficient and timely engineering review necessary t cmply with OSSC requirements. LBE shall assigned prjects t a BE. The BE befre cmmencing a detailed plan review, he r she shall: Make a preliminary review t becme familiar with the verall prject. Verify receipt f cmplete and legible plans, specificatins, calculatins, and getechnical engineering reprt. Cnfirm that the drawings are cmplete enugh t perfrm an engineering review. Cnfirm that calculatins are cmplete enugh t perfrm a plan review. The calculatins shall be sufficiently cmplete t establish that the structure will resist the lads and frces prescribed in OSSC prvisins by means f cmplete lad path. There shuld be n majr discrepancies r errrs such as incrrect seismic factrs, wrng wind lad design, incrrect snw lading, etc. If any dcuments are missing, r incmplete, the BE shuld cntact the AOR / EOR immediately s that deficiencies can be addressed as sn as pssible. The BE must cnsult with LBE if there are any deficiencies in the prject which culd prevent cmmencement f detail engineering review. B. General Engineering Plan Review Methdlgy: - There are many methds fr the BE t rganize the prgress f an engineering review. One suggested sequence is as fllws: 1. Start by develping an understanding f the wrking drawings and expected behavir f the structure, 2. Prceed t a technical review f the structural analysis and verall structural stability f the prpsed structure. 3. Check the prfessinal s design calculatins against the drawings. 4. The BE shuld perfrm his r her wn calculatins fr a few elements in rder t prvide an independent calculatins verificatin t the prject designer's methds are valid. 5. Review drawings fr cnflicting details, dimensins, r ntes are remved, and als that a cmplete and buildable set f drawings is apprved fr cnstructin. B.1 Specific Engineering Plan Review: The BE must use his r her wn judgment, and independent paths f reasning t verify the cnclusin f the design engineer s wrk whenever pssible. It is recmmended that the BE take a mment nw and then t 'step back' frm detailed review f the details and calculatins that have been prvided and think abut what issues may be entirely missing frm the dcuments. If the BE simply fllws the designer's path and reviews the designer's calculatins and details the BE may verlk the same aspects that the designer verlked. B.2 Cmputer Calculatins Department f Land Use & Transprtatin Develpment 3 Services Divisin Building Services Sectin

4 A user s guide must be submitted with cmputer calculatins if it is essential t perfrming the engineering prject review. The BE shall verify all input rientatin, lading, member sizes, dimensins, etc. The BE shuld make every effrt t verify submitted cmputer calculatins whenever pssible withut running anther prgram. The BE may spt-check cmputer utputs by verifying that the summatin f frces is balanced r by making ballpark assumptins such as using prtal r cantilever methds t check frames. The BE may run an independent cmputer analysis when the designer's user guide r input is disputed r is difficult t fllw. Discuss with the LBE befre cmmencing any extensive cmputer runs. Nte: If the designer's cmputer analysis is incnsistent r incrrect then it will have t be crrected: BUILDING SERVICES will nt analyze the entire structure t prve that the designer's cmputer prgram is incrrect. B.3 Architectural, Structural, Mechanical, Plumbing, and Electrical Plans Engineering Review The BE shuld verify that architectural, structural, mechanical, plumbing, and electrical drawings (as well as specificatins) are all crdinated. Since cnsultants usually wrk independently n these aspects f design it is cmmn t find cnsistency errrs. Fr example, lcatins f drs, windws, interir walls, r even verall building dimensins may change n architectural drawings during the design f the prject. If these changes were nt picked up n the structural drawings shear wall lengths and lcatins may be incrrect. Other examples f crdinatin prblems include but nt limited t: Rftp unit lcatin. HVAC ducts ruted thrugh structural elements. Pipe r cnduit riser lcatins interfering with structural shearwalls. Fire rated gypsum bard lcatin cnflicting with structural plywd lcatin. It is essential fr the BE t use his r her structural engineering expertise t lk fr aspects f the design that may be missing frm the drawings and/r specificatins. The BE is encuraged t use standards, charts, cmputer prgrams, and spreadsheets as reviewing aids. C. Cmmunicating Engineering Plan Review Cmments: The BE shall prvide his r her phne number n the cver sheet fr the AOR / EOR. This infrmatin is necessary fr dialgue. The BE shall make cmments that are clear, legible, and cmplete s that designers will easily understand it. Clear cmments will alleviate cnfusin and reduce time spent in revisins review prcess t be knwn as back-check prcess. The BE shuld nt specify any size f members, materials, details, r methds f cnstructin in the cmments, nr shuld calculatins be prvided t the AOR / EOR. The AOR / EOR is required t determine the remedy fr any deficiency that may be discvered by the BE. If pssible, the BE shuld wrd general cmments which apply t numerus drawings s that the cmments dn t need t be repeated. The BE shuld avid crrecting spelling r grammar unless the meaning is nt clear. Typical details n the drawings that are nt used, and are in cnflict with BUILDING SERVICES requirements, shuld be deleted frm the drawings r crrected by the AOR / EOR. Examples f BE Cmment Wrding: Department f Land Use & Transprtatin Develpment 4 Services Divisin Building Services Sectin

5 Use specific cmments such as: Shw cmplete details in accrdance with yur 67 Calculatin page 4. D nt use vague cmments such as: Clarify welding Avid persnalized wrding such as: Yur calc. fr this cnnectin is in errr Prvide cde references fr cmments whenever pssible: Prvide additinal lath supprt at hrizntal sffits per OSSC, Sectin xxxx The BE can make independent calculatins when prtins f the design prfessinal s calculatins are difficult t fllw r interpret: Shear wall is verstressed alng gridline A, wall shears are 520#/ft by independent calculatin D. Suggested D s and Dn ts f Engineering Review: All majr structural prtins f the prject must be substantiated by calculatins as per OSSC prvisins. Example: Prvide cmplete calculatins fr bearing stresses and reinfrcement requirements fr clumn ftings alng gridline B A cmplete calculatin wuld include checking punching shear in the cncrete, bearing and bending stresses n the base plate, sil bearing stresses, required reinfrcement in the fting, required embedment lengths, fting depths, etc The BE shuld nt be required t make calculatins t verify the fting design. The BE shuld nt request additinal calculatins fr items where the capacity can be easily assessed r interplated frm similar cnditins, r is adequate by bservatin. As a basic rule, the BE shuld nt request additinal calculatins unless he r she has determined that the design is questinable. Engineering judgment shuld be used befre asking fr additinal calculatins. It is nt necessary fr the BE t cmment n errrs in calculatins if drawings and specificatins will result in cmpliant cnstructin. Fr example, if calculatins failed t take a reductin factr int accunt, but the element specified is adequate fr the impsed lads anyway (as shwn by independent analysis by the BE), it is nt necessary t write a cmment, since the supprting calculatins are nt part f the cnstructin dcuments. Suspensin f Engineering Plan Review: In the event that a majr design errr is discvered by the BE after the reviewing is well underway, and this errr will result in majr redesign, engineering plan review will be suspended. Immediately cnsult with the LBE if such a cnditin is discvered. Reviewing will be resumed when revised dcuments which adequately address the issue are received. This prcedure is t be used nly under the special circumstances nted abve. The LBE apprval must be btained befre requesting a recheck set f drawings. E. Respnding t Engineering Plan Review Cmments Prcess Scheduling and Plan Review Cmments Respnse Submittal The AOR / EOR is required t call the BE in advance t make an appintment fr Plan Review Cmments Respnse Submittal. Plan Review Cmments Respnse Submittal appintments have pririty ver engineering plan review wrk. The persn r persns representing the AOR / EOR in the back-check must be thrughly familiar with the prject and the plan review cmments/crrectins. Department f Land Use & Transprtatin Develpment 5 Services Divisin Building Services Sectin

6 The Plan Review Cmments Respnse Submittal will be terminated when it is determined by the BE, with the cncurrence f the LBE, that mre than three engineering plan review items have nt been addressed in full, r that new items have been added that require additinal plan review, r that the representative f the AOR / EOR is nt adequately familiar with the prject t address plan review cmments. N mre than tw (2) engineering review letters shuld be sent by BE fr the same items as fund in the riginal review letter withut the cncurrence and apprval f LBE. The BE shuld make every effrt t get issue(s) reslved prir t initiating a third review letter fr unreslved items. In Matters f Differences in Cde Interpretatins and Opinin: When differences f pinin ccur between BE and the AOR / EOR: 1. BE shuld respectfully and lgically explain the reasning behind the cmment. 2. The LBE shuld be cnsulted if the disputed cmment cannt be reslved. 3. Fr differences f pinin cncerning matters f engineering judgment and nt regulated i by a specific prvisin f the cde, the judgment f the AOR / EOR shuld prevail. i Reference: Oregn Structural Specialty Cd; WABO/SEAW White Paper ; and thers. Department f Land Use & Transprtatin Develpment 6 Services Divisin Building Services Sectin