Sponsored by The Boston Association of Structural Engineers and the Structural Engineers Association of Massachusetts

Transcription

1 Commonwealth of Massachusetts State Building Code 780-CMR 9 th Edition Renovation of Existing Buildings Using The International Existing Building Code IEBC 2015 with Massachusetts Amendments Sponsored by The Boston Association of Structural Engineers and the Structural Engineers Association of Massachusetts IEBC 2015 Massachusetts Amendments As of this presentation, the 9 th Edition has not yet been adopted. As of January 12, 2016 the BBRS approved a draft. It is now up to the Executive Office of Administration and Finance to review the document. Following that a public hearing will be held and revisions could come before adoption. 1

2 IEBC 2015 Proposed Massachusetts Amendments 1. Chapter 34 in the IBC 2015 is Deleted 2. Investigation by a Registered Design Professional is mandatory for all renovations and additions to existing buildings including structural and non-structural systems 3. A table of Seismic Design and Analysis Coefficients Unique to Massachusetts 4. Miscellaneous changes, deletions and additions. Alternate Approaches to Remodeling 1. The Prescriptive Compliance Method Chapter 4 2. The Work Area Compliance Method Chapters 5 through The Performance Compliance Method Chapter 14 Appendix A1 to A5 Guidelines for Seismic Retrofit of Existing Buildings 2

3 Alternate No. 1 Chapter 4 Prescriptive Compliance Method Prerequisite An Investigation, Evaluation and report by Registered Design Professionals Shall be required As a condition of issuance of a Building Permit. Shall include structural, means of egress, fire protection, energy, etc. Evaluation and Design shall meet the requirements of (See MA Amendments) Alternate No. 1 Chapter 4 Prescriptive Compliance Method Continued Alterations and Additions Gravity Load Elements Must be strengthened unless the increase in load is less than 5%. Note : The cumulative effect of load increases since original construction shall be Considered. If the live load capacity is less than required by the IBC the area in question shall be posted. 3

4 Alternate No. 1 Chapter 4 Prescriptive Compliance Method Continued Alterations and Additions Lateral Load Resisting Systems All such systems shall be shown to meet IBC Sections 1609 (wind loads) & 1613 (Seismic) unless an increase in Demand/Capacity Ratio is less than 10% Additions can be vertical in which case the lateral system might have to be radically modified. Additions can also be lateral in which case they could be isolated from the original building. Alternate No. 1 Chapter 4 Prescriptive Compliance Method Continued Repairs Where damage has been done to a building s structural components an evaluation shall be done by a Structural Engineer. Repairs must meet the following requirements: 1. Full IBC wind load requirements must be met % of IBC Seismic Requirements must be met. 3. Full IBC Gravity Requirements must be met. Exception If damage is found to be less than substantial repairs may restore the members to pre-damage strengths. 4

5 Alternate No. 1 Chapter 4 Prescriptive Compliance Method Continued Change of Occupancy An increase to a higher occupancy category shall trigger an upgrade to full IBC Seismic resistance for the structure. 1. A structure that by analysis meets these requirements will not require reinforcement. 2. A structure that does not meet these requirements must be reinforced. 3. It should be noted that this change could trigger a seismic upgrade although the structure itself has not been modified Classification of work Repairs, Chapter 6 As defined in Chapter 2 do not include structural repairs. Alterations, Level 1 Shall comply with Chapter 7 (Non-Structural) Where alterations generally do not effect the structure the structural investigation and analysis report must be submitted to prove it. 1. Exceptions: Replacement of roofing and/or Equipment 2. All increases in dead load to roofs of more than 5% will require structural reinforcement. 3. Anchorage of Parapets in unreinforced masonry buildings will be required when the entire roof is removedd. 4. Roof Diaphragm must be investigated if the entire roof is replaced in buildings in areas of 115 mph wind speed and Type IV Essential Facilities. 5

6 Alterations Level 2 Chapters 7 & The level of alteration in this level of work obtains when the area of work is less than 50% of the existing building floor area. Gravity Load Resisting Elements Shall be reinforced unless an increase in load does not exceed 5%. Lateral Load Resisting Elements Shall be reinforced unless an increase in load does not exceed 10%. Alterations Level 3 Chapter 7,8 & The level of alteration in this level of work obtains when the area of work is more than 50% of the existing building floor area. Gravity Load Resisting Elements Shall be reinforced unless an increase in load does not exceed 5%. New elements shall comply with IBC requirements. Lateral Load Resisting Elements Shall meet the IBC requirements for full wind loading and for a reduced seismic loading in conformance with Section

7 Change of Occupancy Chapter Gravity Load Resisting Elements Shall be reinforced unless an increase in load does not exceed 5%. New elements shall comply with IBC requirements Lateral Load Resisting Elements Shall meet the IBC requirements for full wind loading and seismic loading where new occupancy is more than 10% of Building Area. Seismic detailing requirements may be waived. Unreinforced masonry bearing wall buildings may come under Appendix A1 for strengthening. Additions Chapter Gravity Load Resisting Elements Shall be reinforced unless an increase in load does not exceed 5%. New elements shall comply with IBC requirements. Group R (residential structures) are exempt where there are no more than 5 units. 7

8 Additions Chapter 11 continued Lateral Load Resisting System 1. Vertical Additions 1. Shall comply with IBC Wind Provisions. 2. Shall comply with Seismic Provisions Section (using 100% of prescribed forces). Reference to ASCE Shall comply with reduced seismic force levels per Section as defined in ASCE 41. Additions Chapter 11 continued Lateral Load Resisting System 2. Horizontal Additions 1. Shall comply with IBC Wind Provisions. 2. Shall comply with Seismic Provisions Section Irregularities shall be taken into account. 3. Snow Drift Loads Structural elements subject to snow drift shall be upgraded accordingly if increase is more than 5%. Except Group R buildings with less than 5 units. 8

9 Historic Buildings Chapter 12 Re: Massachusetts Historic Commission 1. Compliance is not mandatory. 2. Building is subject to Proof of Historic Building Status. 3. Replacement components may be in kind. 4. A formal structural report is required. 5. If the structure is deemed unsafe it can be repaired so as to be safe. This work shall be done under Chapter 5, except: 1. Building Official may approve of Floor Load by Signage, Limits to Occupancy, Barriers, Etc. 2. House Museums are exempt from Wind & Seismic Provisions. Relocated or Moved Buildings Chapter Foundation shall meet IBC requirements. 2. Connections to the foundation shall meet IBC requirements. 3. Building shall meet IBC wind load provisions. Except One & Two Family dwellings with no change in structure or wind zones more than 10%. 4. Shall comply with snow load provisions unless change is less than 5% 5. Shall comply with seismic provisions. Except for One & Two Family dwellings and Category A & B design categories. 9

10 Chapter 13 Performance Compliance Method 1. An Investigation and Analysis Report must be submitted by a registered design professional as condition of issuance of a Building Permit setting out the parameters of the approach. 2. A Peer Review of the above must be submitted by an independent registered design professional as condition of issuance of a Building Permit. 3. Date of Original Construction is to be established and the Applicable Code in force at the time of construction if possible. 4. Structural Provisions must comply using Chapters 4 to Exception: Residential buildings 3 stories or less of light frame construction and 6 units or less shall be exempt from compliance with loads set out in chapter 16 Conflicts between 2015 Prescriptive and Work Area Provisions 10

11 Question Period After a period of questions, if time permits, the presenter offers an interesting slide show of his Top Ten Structural Picks These are the highlights of issues that he feels are of importance for the Building Officials in regard to Structural issues 11