Seismic Design Requirements

Transcription

1 City of Medford Municipal Code Chapter 9 Presented by the Building Safety Department

2 THESE PROVISIONS PRESCRIBE THE DESIGN REQUIREMENTS OF EXISTING BUILDINGS UNDERGOING: CHANGE OF OCCUPANCY ADDITIONS ALTERATIONS SECTION 9.600

3 FOR CHANGE OF OCCUPANCY AND STRUCTURAL ADDITIONS THE DESIGN STANDARD SHALL BE THE CURRENT EDITION OF OREGON STRUCTURAL SPECIALTY CODE. FOR OTHER WORK COVERED UNDER THESE PROVISIONS THE DESIGN STANDARD SHALL BE FEMA 178, NEHRP HANDBOOK FOR THE SEISMIC EVALUATION OF EXISTING BUILDINGS. SECTION 9.610

4 THE USE OR CHARACTER OF A QUALIFIED HISTORIC BUILDING OR PROPERTY, OR PORTION THERE OF, SHALL BE PERMITTED TO CONTINUE IN USE REGARDLESS OF ANY PERIOD OF TIME IT MAY HAVE BEEN UNOCCUPIED OR IN OTHER USE; PROVIDED THE BUILDING OR PROPERTY OTHERWISE CONFORMS TO ALL APPLICABLE REQUIREMENTS OF THIS CHAPTER. SECTION 9.615

5 THE TABLE BELOW IS USED TO CLASSIFY THE RELATIVE HAZARD OF ALL BUILDING OCCUPANCIES; RELATIVE HAZARD OCC. CLASSIFICATION 5 (HIGHEST) A, E,I-1.1, 1-3, H-1, H-3, H-6, H-7 4 R-1, SR, 1-2, B, I-1.2, I-1.3, M 2 F, S, H-4, H-5 1 (LOWEST) R-3, U SECTION 9.620

6 AN OCCUPANCY CHANGE OF THE SAME OR A LOWER RELATIVE HAZARD CLASSIFICATION NUMBER WILL NOT REQUIRE SIESMIC IMPROVEMENTS, UNLESS THE CHANGE RESULTS IN AN OCCUPANT LOAD INCREASE OF MORE THAN 20% SECTION 9.620

7 AN OCCUPANCY CHANGE TO A HIGHER RELATIVE HAZARD CLASSIFICATION NUMBER WILL NOT REQUIRE SEISMIC IMPROVEMENTS, WHEN THE NET FLOOR AREA OF THE CHANGED PORTION OCCUPIES LESS THAN 15% OF THE NET FLOOR AREA OF THE BUILDING AND WHERE THE CHANGE DOES NOT RESULT IN AN INCREASE IN OCCUPANT LOAD AS DEFINED BY THE OREGON STRUCTURAL SPECIALTY CODE OF MORE THAN 100 PERSONS. SECTION 9.620

8 ALL OTHER CHANGES TO A HIGHER RELATIVE HAZARD OCUPANCY WILL REQUIRE SEISMIC IMPROVEMENTS USING THE CURRENT EDITION OF THE OREGON STRUCTURAL SPECIALTY CODE. SECTION 9.620

9 ALL STRUCTURES, WHICH ARE BEING CONVERTED TO ESSENTIAL FACILITIES, AS DEFINED IN THE OREGON STRUCTURAL SPECIALTY CODE, SHALL COMPLY WITH CURRENT SEISMIC REQUIREMENTS, REGARDLESS OF OTHER REQUIREMENTS IN THIS SECTION. SECTION 9.620

10 AN ADDITION THAT IS NOT STRUCTURALLY INDEPENDENT FROM AN EXISTING BUILDING SHALL BE DESIGNED AND CONSTRUCTED SUCH THAT THE ENTIRE BUILDING CONFORMS TO THE SEISMIC FORCE RESISTANCE REQUIREMENTS FOR NEW BUILDINGS UNLESS THE FOLLOWING THREE CONDITIONS ARE MET: SECTION 9.625

11 THE ADDITION SHALL COMPLY WITH THE REQUIREMENTS FOR NEW BUILDINGS, AND THE ADDITION SHALL NOT INCREASE THE SEISMIC FORCES IN ANY STRUCTURAL ELEMENT OF THE BUILDING BY MORE THAN 5 PERCENT UNLESS THE CAPACITY OF THE ELEMENT SUBJECT TO THE INCREASED FORCES IS EQUAL TO OR GREATER THAN THAT REQUIRED FOR NEW BUILDINGS, AND SECTION 9.625

12 THE ADDITION SHALL NOT DECREASE THE SEISMIC RESISTANCE OF ANY STRUCTURAL ELEMENT OF THE EXISTING BUILDING UNLESS THE REDUCED SEISMIC RESISTANCE OF THE ELEMENT IS EQUAL TO OR GREATER THAN THAT REQUIRED FOR NEW BUILDINGS. SECTION 9.625

13 IF A BUILDING IS DAMAGED BY FIRE, ALL DAMAGED LATERAL LOAD RESISTING COMPONENTS OF A BUILDING S STRUCTURAL SYSTEM MUST BE DESIGNED AND REBUILT TO CURRENT PROVISIONS OF THE OREGON STRUCTURAL SPECIALTY CODE. SECTION 9.630

14 THESE COMPONENTS MUST ALSO BE CONNECTED TO THE BALANCE OF THE UNDAMAGED LATERAL LOAD RESISTING SYSTEM IN CONFORMANCE WITH CURRENT CODE PROVISIONS. UNDAMAGED COMPONENTS NEED NOT BE UPGRADED TO CURRENT LATERAL LOAD PROVISIONS OF THE CURRENT CODE, UNLESS REQUIRED BY OTHER PROVISIONS OF THE OREGON STRUCTURAL SPECIALTY CODE. SECTION 9.630

15 WHEN AND ALTERATION, FOR WHICH A BUILDING PERMIT IS REQUIRED, HAS A VALUE OF MORE THAN $100,000 A FEMA 178 EVALUATION IS REQUIRED. A LETTER OF INTENT TO HAVE A FEMA 178 EVALUATION PERFORMED MAY BE SUBMITTED ALONG WITH THE PERMIT APPLICATION. THE EVALUATION MUST BE COMPLETED BEFORE ANY FUTURE PERMITS WILL BE ISSUED. THE FOLLOWING SHALL BE EXEMPTED FROM THIS REQUIREMENT: SECTION 9.635

16 BUILDINGS CONSTRUCTED OR RENOVATED TO SEISMIC ZONE 2, 2B OR 3 UNDER A PERMIT ISSUED AFTER JANUARY 1, ONE-AND-TWO FAMILY DWELLINGS. SINGLE STORY, LIGHT METAL BUILDINGS LESS THAN 5,000 SQUARE FEET IN AREA. LIGHT WOOD BUILDINGS LESS THAN 5,000 SQUARE FEET IN AREA. A PREVIOUSLY PREPARED SEISMIC STUDY MAY BE SUBMITTED FOR CONSIDERATION BY THE DEPARTMENT AS EQUIVALENT TO A FEMA 178 EVALUATION. SECTION 9.635

17 SEISMIC HAZARDS SHALL BE MITIGATED IN CONJUCTION WITH BUILDING ALTERATIONS AND REPAIRS IN UNREINFORCED MASONRY BUILDINGS, AS FOLLOWS: WHEN THE ROOF COVERING IS REPAIRED OR REPLACED, THE BUILDING STRUCTURAL ROOF SYSTEM, ANCHORAGE, AND PARAPET SHALL BE REPAIRED AND REHABILITATED PER APPENDIX C OF THE DESIGN STANDARDS- FEMA 178, OR SECTION 9.640

18 WHEN THE COST OF ALTERATION WORK WHICH REQUIRES A BUILDING PERMIT IN A 2 YEAR PERIOD EXCEEDS A $15 PER SQUARE FOOT FOR THE TOTAL NET FLOOR AREA IN THE BUILDING, THEN THE BUILDING SHALL BE IMPROVED SEISMICALLY PER SECTION SECTION 9.640

19 COSTS FOR SITE IMPROVEMENTS AND MANDATORY FM41 AGREEMENTS, MANDATED ADA IMPROVEMENTS, MANDATED LANDSCAPING AND MANDATED OR VOLUNTARY SEISMIC IMPROVEMENTS WILL NOT BE INCLUDED IN THE $15 PER SQUARE FOOT AMOUNT. SECTION 9.640

20 THE BUILDING SAFETY DIRECTOR MAY APPROVE A MULTI-YEAR PHASED PROGRAM OF SEISMIC IMPROVEMENTS WHEN THE IMPROVEMENTS ARE PRE-DESIGNED AND AN IMPROVEMENT/IMPLEMENTATION PLAN IS APPROVED BY THE BUILDING SAFETY DIRECTOR. THE MAXIMUM TOTAL TIME ALLOWED FOR COMPLETION OF PHASED IMPROVEMENTS SHALL BE TEN YEARS. SECTION 9.645

21 BUILDING PERMIT APPLICATIONS TO IMPROVE THE SEISMIC CAPABILITY OF A BUILDING SHALL NOT TRIGGER: ACCESSIBILITY IMPROVEMENTS SO LONG AS THE SEISMIC IMPROVEMENT DOES NOT LESSEN ACCESSIBILITY. FIRE LIFE SAFETY IMPROVEMENTS SO LONG AS THE SEISMIC IMPROVEMENT DOES NOT LESSON THE BUILDING S FIRE RESISTANCE OR EXITING CAPABILITY. SECTION 9.650

22 LANDSCAPE IMPROVEMENTS REQUIRED BY THE LAND DEVELOPMENT CODE CHAPTER 10. STREET TREE IMPROVEMENTS REQUIRED BY THE LAND DEVELOPMENTS CODE. CONFORMANCE WITH THESE INTERIM REGULATIONS MAY NOT EXEMPT BUILDINGS FROM FUTURE SEISMIC REQULATIONS. SECTION 9.650

23 BUILDING PERMIT, PLAN REVIEW AND FIRE LIFE SAFETY REVIEW FEES ARE WAIVED WHEN SUCH FEES TOTAL LESS THEN $2,500, AND REDUCED BY 50% WHEN SUCH FEES WOULD TOTAL $2,500 OR MORE. SECTION 9.655

24 BECAUSE UNANTICIPATED CIRCUMSTANCES MAY ARISE IN THE ENFORCEMENT OF THESE REQUIREMENTS FOR EXISTING BUILDINGS, CONSIDERATION AS TO THE REASONABLE APPLICATION OF THIS CHAPTER MAY BE ADDRESSED THROUGH THE UNITED APPEAL BOARD. SEE SECTION THROUGH SECTION 9.655

25 GUIDELINES FOR STRUCTURAL WORK IN EXISTING BUILDINGS APPLICATION FOR WORK ON EXISTING BUILDING ADDITION with LOAD > 5% on BLDG? No CHANGE OF OCCUPANCY (To higher hazard) OR 20% increase of occupant load? No PERMIT VALUE > $100,000? No URM BLDG. Unreinforced Masonry Bldg? Yes PERMIT VALUE >$15/Sq Ft? No ROOF REPAIR 50% or more of roof covering? No Any new structural elements requiring structural design or are fire-damaged structural elements being replaced? No Any work done to existing structural elements? No NO STRUCTURAL REQUIREMENTS Yes Yes Yes Yes Yes Yes Yes Upgrade building to UBC.1994 Upgrade building to UBC.1994 FEMA 178 EVALUATION REHABILITATE, CONFORM TO FEMA 178, appendix C ATTACH WALLS TO ROOF structure and BRACE PARAPETS as needed per FEMA 178, appendix c New elements conform to UBC.1994 Does work cause existing element to become overloaded? (Strength and / or stiffness) No Element can be modified without conforming to code for new work Yes Element must be improved to UBC.1994