HomeMy WebLinkAboutCT 15-08; CARLSBAD RANCH PLANNING AREA 5 (MARBRISA HOTEL 6); CARLSBAD RANCH PA 5 MARBRISA VILLA 62 (FIRST REVIEW); 2024-05-20 GEOTECHNICAL REPORT REVIEW
__________________________________________________________
DATE: May 20, 2024
TO: City of Carlsbad
Land Development Engineering
1635 Faraday Avenue
Carlsbad, CA 92008
Attention: David Rick
PROJECT ID: CD2023-0012
GRADING PERMIT NO.: GR2024-0010
SUBJECT: Carlsbad Ranch PA 5, MarBrisa Villa 62 (1st review)
Items Submitted by Applicant Items Being Returned to Applicant
“Geotechnical Investigation, Autograph Hotel 6,
MarBrisa Circle, Carlsbad, California,” by MTGL,
Inc., dated November 10, 2023.
Written report review comments.
Based on our review of the submitted geotechnical report, we are providing the following
comments that should be addressed prior to the next submittal. Please provide complete and
thorough written responses to all comments.
GEOTECHNICAL COMMENTS:
1. Please review the most current revisions of the grading and building plans for the project
and provide any additional and/or revised recommendations for the proposed project as
necessary.
2. Please expand on the description of the proposed project to discuss the proposed grading
(depths and limits of cut/fill from existing grades necessary to establish proposed grades,
etc.) and heights/types of proposed retaining walls and other proposed improvements
associated with the proposed development.
3. Please provide an updated “Subsurface Exploration Map” (providing all the geotechnical
information currently shown along with the geologic units and locations of any proposed
shoring) using the most current revision of the project grading plan by Excel Engineering
(sheet 3) as the base map.
4. Please provide an updated “Geologic Cross Section A-A’” based on the updated
“Subsurface Exploration Map” requested in Comment #3 above. Along with the geologic
information shown on the current cross section, please also show/label a) any proposed
GR2024-0010
May 20, 2024
Page 2 of 2
shoring and/or temporary slopes necessary to construct the basement level and b) the
over-excavation necessary to address the potential fill/bedrock transition condition for the
basement level of the structure.
5. Please discuss the geologic structure of the Santiago formation bedrock underlying the
existing fill at the site as it relates to the proposed development.
6. Please provide the Seismic Design Category for the project in accordance with Section
1613 of the 2022 California Building Code and ASCE 7-16.
7. Please provide a statement addressing the condition and stability of the existing slopes
bounding the building pad of the subject site as they relate to the proposed development.
8. Please provide the minimum reinforcement requirements for conventional foundations
from a geotechnical standpoint.
9. Please provide geotechnical recommendations (minimum pile diameter, geotechnical
parameters) for piles associated with any proposed shade structures, etc., or shoring if
necessary.
10. Please clarify the recommended inclination for cut slopes, as Section 4.01.10 (page 17,
Slopes) indicates all permanent slopes should be constructed no steeper than 2:1 (H:V)
but also indicates cut slopes constructed no steeper than 1.5:1 (H:V) will possess an
adequate factor of safety. Per the City of Carlsbad grading ordinance, permanent graded
slopes shall be no steeper than 2:1 (H:V).
11. Please coordinate the specifications for concrete that are provided on Page 21 in Section
4.03 under “Interior Slabs on Grade” (3000 psi with w/c ratio of 0.50) with the
recommendations for concrete design provided on Page 22 in Section 4.06 under
“Corrosivity” (“Moderate” sulfate exposure (S1), 4000 psi with w/c ratio 0.50 and Type II/V
cement).
12. Please add a) retaining wall subdrains and backfill, b) fill placement, c) temporary
excavations and/or shoring, d) pile excavations, e) hardscape subgrade, and f) import
soils, to the list of geotechnical observations and testing that should be performed as part
of the proposed development.