The Golden Gate Valley Branch Library has CLOSED for renovation
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| BACKGROUND |
| Year Built: |
1917 |
| Architect: |
Ernest Coxhead |
| Seismic Hazard Rating |
3 |
| Number of Stories |
One w/ Basement |
| Type: |
Carnegie |
| Address: |
1801 Green Street |
| Gross Sq. Ft.: |
6,259 |
PRELIMINARY ASSESSMENT
The recommended seismic strengthening is to improve the building performance to provide life safety for the building occupants and substantially reduce the potential for catastrophic (non-repairable) damage to the building in the event of a major earthquake while preserving the historic character of the existing building. The structural retrofit project will add plywood sheathing to the roof, add sway bracing, roof-wall anchors, and steel trusses to strengthen the building.
The original ceiling and wall construction will be temporarily braced throughout making the main reading room unusable during construction. Stairway, restrooms, staff room, electrical room, mechanical room will be modified or relocated to conform to accessibility requirements, life safety related code requirements.
The roof construction is made of wood board sheathing and wood trussed rafters over the main space and wood joists over the alcove space. The floor construction consists of a 6 ½" thick concrete slab over a basement at the west half and over a crawl space at the east half of the building. The walls are reinforced concrete and unreinforced brick bearing walls over continuous concrete wall footings.
Given the historic significance of the building, a careful review will be made to determine the most appropriate disabled access modifications. The scope of disabled access work anticipated includes: the addition of an elevator; re-planning existing restrooms and adding new restrooms; new fire stair; accessible "blue curb" parking zone; modification of counters, bookshelves and table spacing at the reading room areas; and modification of doors and stairways.
Conformance with the latest life safety related code requirements will include: providing a larger electrical room, elevator, and elevator machine room; providing a wider fire stair; providing new accessible restrooms, and wider library aisles.
Conformance with building code involves the updating of the heating, ventilating, plumbing, fire protection, electrical and other building control system to bring it up to code requirements for life safety. Special attention will be placed on preserving the unique historical character of the existing building, on both exterior and interior of the building.
Current law requires removal of asbestos-containing materials (ACMs), including plasterboard walls, floor tiles, and roofing related to the anticipated construction activities associated with seismic retrofit and disabled access construction work. The removal of ACMs will require relocation of the building occupants. Lead will also have to be abated.
The recommended modernization plan will preserve the exterior of the historically significant building. The interior of the building will be remodeled. The seismic retrofit for this building may be more expensive than on a comparable non-historical building. The interior remodel and seismic work trigger conformance work on the American with Disabilities Act (ADA). The modernization work may reduce the area of the library.
A careful study will be done to recover the area lost due to modification.
Improvements also include updating the meeting/program space, redesigning public service points, expand staff work area and reconfigure with security and operational issues in mind; and adding electrical/data outlets to floor and wall in all needed areas, including meeting space. Exterior work will include repointing of exterior façade and miscellaneous site repairs.
ASSESSMENT DETAIL
SEISMIC
- The 1x straight board sheathing on the high and low roof does not have sufficient shear strength capacity.
- Concrete window pier shear walls along the south elevations are discontinuous. There is a visible horizontal crack along the exterior side of this wall directly above the large opening that is indicative of structural distress of the header beam due to the overturning forces of the window pier walls.
- Interior plastered partition shear walls do not have sufficient shear capacity.
- The vertical wall reinforcement is not doweled into the foundation.
- Seismic force generated by the residential building on the south property line may batter the alcove diaphragm.
- The main floor structural concrete slab has noticeable warping in some locations.
Non-Structural Deficiencies
- Partitions and fixed glass windows are not detailed to accommodate story drift.
- Suspended plaster coffered ceiling and light fixtures are not braced.
- Terra cotta wall anchors are corroded.
- Book cases, shelves and stacks are not adequately braced.
- Mechanical equipment (water heater and furnace) are not adequately braced.
- Unreinforced brick fence/retaining wall at the west courtyard needs to be strengthened.
PRELIMINARY RECOMMENDATIONS
- Add new plywood sheathing over existing 1x straight sheathing both at high and low roof.
- Construct new shear walls atop existing W12 wide flange beams.
- Install anchors along URM wall and along concrete bearing walls.
- Re-sheath interior partitions with plywood sheathing. Anchor shear wall at each end and to concrete floor slab.
- Install new steel channels on both sides of existing concrete header beam over the reference nook.
- At the bottom side of main floor slab along the south retaining wall, chip away spalling concrete and repair by shotcreting. Epoxy grout all slab cracks greater than 1.0mm in width.
- Construct new shotcrete wall to strengthen the unreinforced masonry brick fence at the courtyard.
- Brace book stacks and water heater.
- Dry pack gap at the base of the north-west wall with non-shrink grout.
- Brace existing coffered ceiling and light fixtures.
- Replace terra cotta wall tile anchorage tie wires.
ACCESSIBILITY
- Existing building is not accessible to patrons with disabilities.
- Existing Service counters are not accessible.
- Existing toilets are not accessible.
- Existing doors are too narrow and not accessible.
PRELIMINARY RECOMMENDATIONS
- Provide and install new elevator. Build a new concrete ramp in front of the building, starting from the sidewalk to the main floor.
- Install new accessible service counters.
- Renovate existing toilets to make them accessible. Install new toilet fixtures.
- Widen existing door openings and install new doors and hardware that comply with ADA requirements.
MECHANICAL
- Need to upgrade existing radiant heating system.
- Need to upgrade existing water heater and water pipes.
PRELIMINARY RECOMMENDATIONS
- Upgrade heating system. Install new boiler.
- Install new water heater and water pipes.
- Replace existing ducts and piping as required.
- Provide continuous ventilation in all restrooms during hours of library operation.
ELECTRICAL
- The existing service panel is small with no provision for additional breakers. The grounding is improper and unreliable. The interrupting capacity of the main and feeder breakers is unknown.
- Existing light fixtures are inefficient. Lighting panel is inadequate.
- Lack of electrical outlets and data.
- The telecommunication and network equipment is not bonded to the power system grounding electrode.
PRELIMINARY RECOMMENDATIONS
- Install new main service panel with surge protector and integral RFI/EMI filtering to protect sensitive loads such as computers and any new electronic equipment in the building. Segregate power, clean power for computer system and separate power for all others.
- Replace existing light fixtures with new energy saving fixtures and, preserve historical fixtures if possible. Replace lighting panel and upgrade all associated wiring.
- Install additional data/communication outlets.
- The telephone and network protectors should be bonded to the incoming water line within 5 feet of its building entry. Separate room for telecom closet.
LIFE SAFETY/SECURITY
- Need fire alarm and smoke detectors.
- Not enough Exit signs in the building.
- Need emergency lighting at exit corridors in case of power failure or in emergencies.
- Need fire sprinkler along exit path.
- Need security grilles.
- Need additional fire extinguishers in the building.
- Need book security sensor.
- Need security lights in and at the side yard of the building.
- Existing window and door grilles need to be replaced.
PRELIMINARY RECOMMENDATIONS
- Install new smoke detectors and fire alarm.
- Install new exit signs and emergency lights.
- Install fire sprinkler system along exit path.
- Install new fire extinguishers at strategic locations in the building.
- Install new book security sensor.
- Install new interior and exterior security lights.
- Install new window and door grilles.
MATERIALS MITIGATION
- Asbestos Containing Materials (ACM’s) are identified throughout the building.
PRELIMINARY RECOMMENDATIONS
- Where impacted by construction, abate asbestos in vinyl floor tiles and mastics, window caulking and glazing putty, steam piping and fitting insulation, and roof felt on parapet wall.
- Lead that is impacted by construction shall also be mitigated.
MODERNIZATION
- With the seismic retrofit work, valuable library floor space will be lost.
- Minimal staff work and storage areas.
PRELIMINARY RECOMMENDATIONS
- The existing library has no space to expand so a careful study will be done to minimize the area lost due to renovation work. Both floors of the building will be redesigned and upgraded to function more efficiently. Interior finishes will be upgraded.
- Preserve the historic character of the building, particularly the ornate interior of the main reading room and terra cotta exterior finish of the building.
- Upgrade or replace existing windows with new operable windows for air circulation during hot weather days, while preserving the historic character of the structure.
LANDSCAPING
- Existing landscaping on the sidewalk in front of the building.
PRELIMINARY RECOMMENDATIONS
- Develop a landscape preservation, upgrade and maintenance plan.
Send comments or questions about this page to blip@sfpl.org
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