HOW TO EVALUATE BUILDINGS AND DETERMINE RETROFIT COSTS

Transcription

1 David Bell PJHM Architects, Inc. Young Nam Daniel Traub Thornton Tomasetti how to evaluate buildings and determine retrofit costs HOW TO EVALUATE BUILDINGS AND DETERMINE RETROFIT COSTS Presented by: David Bell, AIA, PJHM Architects Inc. Young Nam, S.E., Thornton Tomasetti Daniel Traub, S.E., Thornton Tomasetti

2 REGULATIONS ASSEMBLY BILL (AB) 300, 1999 (CORBETT) REQUIRED DGS TO DO AN INVENTORY OF PUBLIC SCHOOL BUILDINGS THAT TO NOT MEET 1976 U.B.C U.B.C. ADDED SEISMIC PROVISIONS IN REACTION TO RECENT EARTHQUAKES REGULATIONS DGS REPORT, ISSUED NOVEMBER, 2002 INVESTIGATED BUILDINGS BUILT BETWEEN 1933 AND PASSAGE OF THE FIELD ACT AS REACTION TO 1933 LONG BEACH EARTHQUAKE

3 REGULATIONS ADOPTION OF 1976 U.B.C, SO ALL BUILDINGS APPROVED AND BUILT AFTER 1978 ASSUMED TO BE COMPLIANT WOOD FRAMED BUILDINGS EXEMPT FROM INVENTORY: 80% OF BUILDINGS, 379M SQ. FT. BUILDINGS INVENTORIED ARE CONCRETE TILT- UP AND/OR HAVE NON-WOOD FRAMED WALLS REGULATIONS BUILDINGS SORTED INTO TWO CATEGORIES: CATEGORY 1: EXPECTED TO PERFORM WELL IN AN EARTHQUAKE 2,122 BUILDINGS, 27M SQ. FT. CATEGORY 2: NOT EXPECTED TO PERFORM AS WELL AS CATEGORY 1 BUILDINGS IN AN EARTHQUAKE 7,537 BUILDINGS, 65M SQ. FT.

4 REGULATIONS PROPOSITION 1-D, PASSED NOVEMBER, 2006 $7.3 BILLION FOR K-12 CONSTRUCTION $199.5 MILLION AVAILABLE FOR SEISMIC RETROFITS REGULATIONS BEING DEVELOPED TO DETERMINE HOW AND TO WHOM THOSE FUNDS ARE DISTRIBUTED DSA HAS IDENTIFIED 142 BUILDINGS AS BEING THE MOST VULNERABLE CALIFORNIA BUILDING CODE 2001 EDITION CURRENTLY, 2007 EDITION EFFECTIVE JANUARY 1, ASSEMBLE TEAM SEISMIC MITIGATION PROGRAM 2. INITIAL STUDY Establish Evaluation Approach Verify Buildings Establish Seismic Performance Objectives 3. EVALUATION Different Approaches Cost Estimate Prioritize PRESENTATION FOCUS 4. POST EVALUATION Modernizations 5. FUNDING 6. IMPLEMENTATION

5 INITIAL STUDY 1. VERIFY THE FOLLOWING FOR THE BUILDINGS 1. Building exists / Still part of District 2. No previous seismic retrofit * 3. Verify Category 1 or 2 (or neither) 2. ESTABLISH SEISMIC PERFORMANCE OBJECTIVES Damage Control Life Safety Collapse Prevention 3. DEFINE SCOPE OF WORK Evaluation Approach Cost Estimate Approach * MAY NEED INPUT FROM STRUCTURAL ENGINEER PERFORMANCE LEVELS Collapse FEMA DESIGNATIONS Continuous Operation Immediate Occupancy Life Safety AB 300 DESIGNATIONS Damage Control Collapse Prevention

6 EVALUATION TYPES 1. PROPOSITION 1D APPROACH (WITH OR WITHOUT FUNDING) 2. FEMA 310 / ASCE 31 ASSESSMENT 3. CURRENT CODE EVALUATION CAN ALSO BE A HYBRID OF THE ABOVE APPROACHES PROP 1D APPROACH BASED ON AB 300 REPORT & PROP 1D ADDRESSES ONLY MOST VULNERABLE BUILDINGS WILL NOT IDENTIFY OTHER BUILDINGS THAT MAY HAVE SEISMIC DEFICIENCIES AND LIFE SAFETY RISKS

7 SUGGESTED CRITERIA BY DSA TO IDENTIFY MOST VULNERABLE BUILDINGS * CRITERIA 1 Site Acceleration > 1.55 g NO * State Allocation Board Implementation Committee Meeting August 3, 2007 Yes CRITERIA 2 Category 2 and Building Type C1, PC1A, PC2 OR URM NO Yes Does Not Qualify for Prop 1D Funding CRITERIA 3 Occupied by Students & Teachers NO Yes CRITERIA 4 Report from Structural Engineer (Assessing Collapse Prevention) Yes NO Apply for Prop 1D CRITERIA 1 Site Acceleration > 1.55 g Northern California Eureka 1.55 g San Francisco San Jose

8 CRITERIA 1 Site Acceleration > 1.55 g Southern California 1.55 g Los Angeles Riverside CRITERIA 2 Definitions based on DSA study pursuit to AB 300: SEISMIC SAFETY INVENTORY OF CALIFORNIA PUBLIC SCHOOLS MOST VULNERABLE BUILDING TYPES IN CATEGORY 2 C1 - Concrete Moment Frame PC1A Precast/Tilt-Up Concrete Shear Wall with Flex. Diaphragm PC2 Precast Concrete Frame and Concrete Shear walls URM Unreinforced Masonry Bearing Wall (Includes those previously retrofitted with gunite walls) (Note this is only 4 of 12 building types identified in Category 2)

9 BUILDING TYPES C1 PC1A PC2 URM CRITERIA 3 & 4 OCCUPIED BY STUDENTS AND TEACHERS Verify the usage of the building REPORT FROM STRUCTURAL ENGINEER * The lateral force resisting system does not meet collapse prevention performance Provide specific deficiencies and reasoning that the building has a potential for catastrophic collapse * Probably Requires A FEMA 310 / ASCE 31 and or FEMA 356 / ASCE/SEI 41 Type Assessment

10 FEMA 310 / ASCE 31 APPROACH TYPES OF EVALUATIONS THAT CAN BE PERFORMED (The selected type will depend upon evaluation objectives) 1. Category 2 Buildings Only Addresses Most Vulnerable buildings identified by DSA May want to first verify that buildings classified correctly to Category 2 FEMA 310 / ASCE 31 APPROACH 2. All Category 1 & 2 Buildings Provides comprehensive understanding of seismic risk for the District Identifies other Life Safety concerns (Including Category 1 buildings) Provides opportunity to implement other Life Safety retrofits into modernization program Able to obtain total cost for retrofit of all buildings Does not necessarily bring building up to current structural code

11 FEMA 310 / ASCE 31 APPROACH 3. All Buildings Similar to previous except, includes buildings not reviewed during AB 300 study (wood frame & post 1978 buildings) Verifies that buildings were correctly classified CURRENT CODE APPROACH SOME DISTRICTS WISH TO BRING BUILDING UP TO CURRENT CODE TYPICALLY MORE EXPENSIVE, BUT NOT NECESSARILY NOT ALWAYS POSSIBLE STRUCTURAL ENGINEER PERFORMING RETROFIT MAY BE MORE FAMILIAR WITH CURRENT CODE THAN FEMA 356 / ASCE 41

12 ESTABLISHING COSTS PER DSA (AS RECOMMENDED TO SAB 8/3/07): $60 PER SQ. FT. COST TO RETROFIT 142 IDENTIFIED BUILDINGS = 1,760,000 SQ. FT. = $106 MILLION IN CONSTRUCTION COSTS SOFT COSTS ESTIMATED AT 29%, $31 MILLION = TOTAL OF $137 MILLION (2002 DOLLARS) ADJUSTED TO $169 MILLION (2007 DOLLARS) DOUBLE COSTS TO ACCOUNT FOR OTHER REQUIRED WORK = $338 MILLION $338 MILLION / 142 MOST VULNERABLE = $2.38 MILLION PER BUILDING (STATE + LOCAL FUNDS) ASSESSING COSTS INDIVIDUAL PROJECT COSTS VERY SITE SPECIFIC! DEPENDS ON SITE, BUILDINGS, EVALUATION FINDINGS AND MITIGATIONS DSA REQUIRED SCOPE OF WORK ACCESS COMPLIANCE & FIRE LIFE SAFETY UPGRADES REQUIRED

13 ASSESSING COSTS - CBC 1134B.2.1 A PRIMARY ENTRANCE TO THE BUILDING OR FACILITY AND THE PRIMARY PATH OF TRAVEL TO THE SPECIFIC AREA OF ALTERATION, STRUCTURAL REPAIR OR ADDITION, AND SANITARY FACILITIES, DRINKING FOUNTAINS, SIGNS AND PUBLIC TELEPHONES SERVING THE AREA MATERIAL COSTS ASSESSING COSTS EDUCATION DELIVERY COSTS SPATIAL IMPACTS CLASSROOM IMPACTS

14 PRIORITIZE PRIORITIZE MOST VULNERABLE BUILDINGS BASED ON AB 300 CRITERIA IDENTIFY RELATIVELY EASY FIXES ALLOW TO MAKE AN INFORMED DECISION / PLANS POST EVALUATION (now what?) DO YOU HAVE A PROJECT (FUNDING)? DSA ESTIMATE - $2.38 MILLION PER BUILDING 60% STATE / 40% LOCAL: $1.43M STATE / $950,000 LOCAL DISTRICT SPECIFICS STATUS / SOURCE OF LOCAL FUNDING? PURSUE HARDSHIP? MODERNIZATION PROGRAM?

15 PROGRAM THE PROJECT TYPE OF PROJECT: SEISMIC RETROFIT OR FULL MODERNIZATION? DSA REQUIRED SCOPES FULL MODERNIZATION BENEFITS PLAN THE PROJECT MODERNIZATION WITH GREATER STRUCTURAL COMPONENT PROJECT TIMING / SCHEDULE SUMMER VACATION OR LONGER? MATERIAL LEAD TIMES INTERIM HOUSING?

16 CASE STUDIES PRE - AB 300 As part of a modernization Stand alone IN RESPONSE TO AB 300 RESOURCES 1. USGS Seismic Acceleration Maps 2. Seismic Safety Inventory of California Public Schools (AB 300 Report) 3. FEMA 424 Design Guide for Improving School Safety in Earthquakes, Floods and High Winds