B08_Attach_4_Drawings_GOGA_Conzelman_Road_Wall_-_Final_CD.pdf

This document is a set of construction drawings for the Repair Conzelman Road project at Golden Gate National Recreation Area in Marin County, California. The project, identified as NPS GOGA 336173, involves structural engineering, civil engineering, and survey work prepared by Coffman Engineers Inc. and Guida Geospatial Solutions.

The construction scope includes demolition and removal of existing asphalt pavement, concrete curbing, and damaged guardrails along a section of Conzelman Road. The project involves installation of new asphalt pavement (4 inches thick in two lifts), a new retaining wall with concrete pile foundations, and new guardrail systems including bridge rail details. Key structural elements include six concrete piles (2.5-foot diameter, spiral-tied with #4 ties at 2.5-inch pitch), a concrete grade beam, and a retaining wall with French drainage and weep holes. The design incorporates erosion and sediment control measures including wattles and erosion control blankets on slopes. Construction staging areas, excavation limits, and grading requirements are clearly delineated. The drawings reference California Standard Plans for bridge rail details (ST-75 series) and Midwest Guardrail System (MGS) standards, with specifications for reinforced concrete (5,000 PSI), reinforcing steel (ASTM A615 Grade 60), and standard lap splice schedules. The project includes detailed cross-sections, typical details, and coordination notes for utilities, foundation design per geotechnical report by Terracon (dated February 23, 2026), and compliance with 2025 California Building Code requirements. Design completion date is July 10, 2026.