Loading...
HomeMy WebLinkAboutPCD/GPC 90-09; Carrillo Ranch Restoration; Planning Comm Determ/Gen Plan Consis (PCD/GPC)6HA/ STAFF REPORT DATE: DECEMBER 19, 1990 TO: PLANNING COMMISSION FROM: PLANNING DEPARTMENT SUBJECT: PCD/GPC 90-9 - GENERAL PLAN CONSISTENCY DETERMINATION FOR THE CITY OF CARLSBAD CARRILLO RANCH STABILIZATION AND RESTORATION PROJECT. I. RECOMMENDATION That the Planning Commission ADOPT Resolution No. 3172 approving PCD/GPC 90-9 making the determination that the Carrillo Ranch Stabilization and Restoration Plan is consistent with the General Plan. II. PROJECT DESCRIPTION AND BACKGROUND Prior to the approval of building plans for a public works project, the Planning Commission must determine that the project is consistent with the General Plan per Section 65401 of the California Government Code. During the past three years, $490,000 in historic preservation grants have been awarded to the City by the State Department of Parks and Recreation for stabilizing and restoring the existing structures at Carrillo Ranch. Architect, Milford Wayne Donaldson, was employed in 1988 to develop a stabilization and restoration plan. This plan has been completed and includes an analysis of the condition of each of the structures at the site along with recommendations for their stabilization and restoration. Detailed plans and specifications incorporating the recommendations prepared by the consultant will be submitted for building permits after Planning Commission approval of the required General Plan consistency determination. The stabilization project generally includes work on all of the existing structures and consists of the installation of supports, braces, and the anchoring of structures to foundations and roofs. No new construction is proposed. III. ANALYSIS Planning Issues 1. Is the proposed Carrillo Ranch Stabilization project consistent with the General Plan? PCD/GPC 90-9 - CARRILLO RANCH STABILIZATION DECEMBER 19, 1990 PAGE 2 DISCUSSION The proposed Carrillo Ranch stabilization project described above is the first step in preserving and rehabilitating the site and therefore, is consistent with the following General Plan goals and policies: Land Use Element Goal F: Protect and conserve natural resources, fragile ecological areas, unique natural assets and historically significant features of the community. The Land Use Element designates Carrillo Ranch as a Special Resource Area, defined as a local amenity "under the jurisdiction of the City of Carlsbad that has either City-wide or potential regional significance. Significance is found within each site's unique potential to attract users from a greater distance than a local facility." Park & Recreation Element Carrillo Ranch is designated in the Park & Recreation Element as a special resource area. The structures "provide an opportunity to connect the future to the past and provide the basis for site rehabilitation to the original historic theme." Policy A-4: "Historically significant sites shall be combined with recreational learning opportunities where possible." 1.4:1 Action Plan: "Develop the Leo Carrillo Ranch as a commercial recreational opportunity that identifies the site's original historical significance." Historic Preservation Element The Carrillo Ranch site has received a historical designation by the Historic Preservation Commission. Goal: "To provide for the protection, preservation, recognition and enhancement of the City's existing and continuing heritage." Objective: "Promote the use of historic resources for the education, pleasure and welfare of the people of the City." Open Space Element Goal 3: "To prevent incompatible development of areas that should be preserved or regulated for scenic, historic, conservation, or public health and safety purposes." Policy 6: "To conserve, develop, and utilize areas particularly suited for outdoor recreation by preserving areas of unique scenic, historical, and cultural value and developing areas especially suited for active park and recreation purposes." PCD/GPC 90-9 - CARRILLO RANCH STABILIZATION DECEMBER 19, 1990 PAGE 3 Growth Management The City initiated construction project is excluded from the requirements of the Growth Management Ordinance per Chapter 21.90.160 of the Municipal Code. IV. ENVIRONMENTAL REVIEW On February 1,1990, the Planning Director issued a Notice of Exemption for the project per Section 15301(d) of CEQA which exempts the restoration or rehabilitation of deteriorated structures from environmental review. SUMMARY Based on the above consistency findings, staff recommends that the Planning Commission make the required General Plan consistency determination for the Carrillo Ranch Stabilization project. ATTACHMENTS 1. Planning Commission Resolution No. 3172 2. Location Map 3. "Structural Analysis and Recommendations" dated July 19, 1989, p 1-6. 4. Memorandum dated November 1, 1990 5. Notice of Exemption dated February 1, 1990 November 19, 1990 AH:rvo City of Carlsbad CARRILLO RANCH PARK PCD/GPC 90-09 Leo Garrillo Ranch Structural Evaluation of Buildings M. Wayne Donaldson, Architect Prepared for City of Carlsbad Submitted by Melvyn Green and Associates, Inc. July. 1989 Introduction and'Scqpe In support of the efforts of the City of Carlsbad to rehabilitate the Leo Carrillo Ranch for community recreation purposes, Melvyn Green and Associates has conducted a structural inspection of the adobe, wood and other structures on the site. The purpose of this inspection was to determine the buildings' structural condition, rehabilitation methods and the options for seismic strengthening of each building. Description Site Layout Buildings are separated into several areas on the site. The main ranch house, wash house, cabana, cantina and carriage house are grouped close together. On a hill above these is "Deedie's" house. At the entrance to the site are the bridge, dam and gate house. Up the hill behind the ranch house are the stable, equipment shed, barn, and water tank. A dam also is in this area; however, dams are regulated by others and this one was not inspected as part of this report Building Construction • General Typical construction of the adobe structures consists of adobe walls on foundations of stone covered with concrete. Roof framing consists of rafters, typically open beams or trusses, with straight board sheathing for the roof. The roof covering is Spanish tile. Some of the "adobe" structures have some wood frame exterior walls. These are simple 4 inch thick walls. The wood frame structures, such as the barn, are constructed of a variety of stud walls, post and beam and bracing systems. The roofs are rafters or built-up trusses with straight sheathing and shake roofing. Analysis-Procedure Compliance with the State Historic Building Code (SHBC) provisions for adobe buildings is the first primary evaluation methodology. Areas where compliance with the SHBC was not considered cost effective are noted and the implications of this discussed. The basic criteria are as follows: Wall stability - this is based on the height to thickness (h/t) ratio of the walls. Exterior walls are permitted a maximum h/t of 5. Interior walls must be a minimum of 10 inches thick, with no h/t criteria. Each wall must have a reinforced concrete bond beam on top. This beam acts as a collar and assists in keeping the structure together. It also provides a means of bracing the walls and transferring lateral shear forces into diem. Other elements to be considered include the roof diaphragm, anchor bolts between roof and wall, and condition of the roof framing lumber. A general overview of the building construction issues includes consideration of whether the roof is strong enough to support the dead load and service loads, including construction workers or city maintenance personnel working on the roofs of the structures. Observations The adobe interior and exterior walls are of sufficient strength to support the roof and other vertical loads. Where they are deteriorated they should be repaired in kind to provide the original design thickness. Earthquake loads are different. The heavy mass of the structure results in large loads on the resisting elements. For example the roof sheathing has to be sufficiently strong to brace the walls against collapse. To accomplish this the roof must be fastened to the wall in a positive manner and the roof sheathing must be stiff enough to resist any loads. Adobe buildings should have a concrete bond beam at the top of the walls. Construction of a bond beam requires removal of the roof framing. This would be destructive to the roof tiles and very costly. Some of the existing sheathing is rotted and may require replacement anyway; on these buildings the concrete bond beam can be installed as part of the necessary rehabilitation. An alternate system is the installation of a stiff steel angle at the roof just under the roof rafters. This angle is attached to the wall with bolts. It is also attached to the rafters and sheathing to provide a tie between the walls and roof. Recommendations Each of the building types observed on the site requires some typical structural upgrading, such as seismic strengthening; and repairs, such as replacement of rotted wood members. All work should comply with the State Historic Building Code. For seismic strengthening the code requires a continuous path for stress resolution. This is easily accomplished in the wood frame buildings by additional nailing, metal connectors and straps and anchor bolts where possible. Adobe structures have different seismic criteria, including criteria for wall height to thickness ratios for exterior walls. Interior walls must be a minimum of 10 inches thick. Exterior walls must have a concrete bond beam at the top, approximately 8 inches deep with reinforcing steel. The roof diaphragm must be positively connected to the walls. This provides the continuous stress path noted above. The procedure for strengthening the adobe structures in compliance with the SHBC would involve removal of the roof tile, sheathing and framing; installation of the concrete bond beam and reconstruction orreinstallation of the roof framing and tile. Obviously this would be an expensive effort and may result in significant loss of the original tile. Based on these probable costs alternate solutions should be considered. Considering the fact that the structures have low walls and numerous cross walls, use of an alternate bond beam solution is possible. A steel angle installed against the wall and the ceiling joists should be considered as an alternate to the concrete bond beam. The angle would be fastened to the adobe with a epoxy type anchor and to the rafters with lags or similar fasteners. The anchors in the adobe would be designed for low loads to distribute the forces along the length of the wall. The angle would probably be visible on the inside of the building but could be painted to match the wall and ceiling colors. This solution would provide a bond beam to brace the wall and distribute the forces. It is not as complete a tie as the concrete bond beam. Structural damage from an earthquake would be greater than with the concrete bond beam alternative, however in either case the damage should not be life threatening. Vertical load carrying capacity of the various roofs is minimal. They all are capable of supporting the tile and framing but no additional loads should be placed on them. It is recommended that the following be done: Repair all deteriorated wood structural members. Install a steel or concrete bond beam at the top of each adobe wall for connection to the roof diaphragm. The exact solution will depend on the amount of deteriorated wood members requiring replacement For buildings with a single adobe wall, a similar bracing system should be installed to tie the wall to the roof. Gable ends of adobe walls should be braced at both the ceiling line and the roof line. In some cases it may be necessary to install a diagonal steel angle from the "ceiling" line to the roof framing. Additional blocking in the roof will have to be installed to take the thrust of the wall brace. Wood frame structures require attachment to the foundation with anchor bolts into the concrete and stone. Wood walls should be rationalized with a stud or a post and beam system. Existing diagonal bracing systems should be augmented with additional braces where practical. The following pages describe the individual structures and give additional specific recommendations for each. NOVEMBER 1, 1990 TO: MUNICIPAL PROJECTS MANAGER FROM: Associate Engineer STATUS REPORT FOR RANCHO CARRILLO STABILIZATION - PROJECT NO. 3306 The stabilization work involves improvements to the various buildings on the Rancho Carrillo site in order to meet seismic stability requirements and repair deteriorated roofs and foundations which are prone to cause water intrusion problems. A Building Permit will be required. The State and City are reviewing building plans. The Planning Department determined the project is categorically exempt under Section 15301, Class 1 (a) and (d) of CEQA on January 31, 1990. A General Plan Consistency finding will be required. The item will be scheduled for the Planning Commission on December 19, 1990. Of the $490,000 available, $332,280 will be spent on construction, and $157,720 on professional fees. A meeting has been scheduled with the Citizen Steering Committee on November 8, 1990 to verify the construction priorities, since some of the repairs will not take place due to funding limitations. The repairs will provide a band-aid, as far as stabilizing the site for future uses. The big problems of access and site drainage must be solved by future construction, which will best be addressed when a master development plan has been established. The project is scheduled for bid awards in February, 1991. DAN CLARK Project Manager \ DC:jkb c: Ann Hysong, Planning Department City of Carlsbad Planning Department I *NOTICE OF EXEMPTION •: .>R ' L E m[j3 Robert D. Jumwalt, Clwk MJI February 1, 1990 F£B,0 5 1990 6T County Clerk ; County of San Diego £ 220 West Broadway San Diego, CA 92101 Pro.iect Title Carillo Ranch Stabilization Project Pro.iect Location—Specific APN: 222-011-03 Pro.iect Location—City Carlsbad Pro.lect Location—County San Diego Description of Nature, Purpose, and Beneficiaries of Pro.iect - Stabilization/restoration of Carillo Ranch House designated as a historic site Name of Public Agency Approving Pro.iect City of Carlsbad Name of Person or Agency Carrying Out Pro.lect Municipal Projects Div., Engineering Department City of Carlsbad Exempt Status (Check One) Ministerial (Sec. 15073) Declared Emergency {Sec. 15071 (a)} Emergency Project {Sec. 15071 (b) and (c)} X Categorical Exemption. State type and section number: Section 15301 Class l(a) and (d) Reason Why Pro.iect is Exempt: Stabilization/Restoration of existing facility Contact Person: Anne Hysong (619) 438-1161 ext. 4328 If filed by applicant: 1) Attach certified document of exemption finding. ; ' 2) Has a notice of exemption been filed by the public •.,> agency approving the project? Yes No MICHAEL J. HOLZMILLER Planning Director 2O75 Las Palmas Drive • Carlsbad, California 92OO9-4859 - (619) 438-1161