rv.I("""[01] Seismic Demands for Carport Braces and Beam Connections
|| image | elements.jpg | 70
Column and Brace Numbers [f]_
|| image | beams2.jpg | 50
Beam Numbers [f]_
|| image | pins.jpg | 90
Element Pin Connections [f]_
|| image | forceA.jpg | 90
Axial Forces - Transverse Seismic [f]_
|| image | forceB.jpg | 90
Axial Forces - Longitudinal Seismic [f]_
|| image | deltA.jpg | 90
Deformations - Transverse Seismic (visually amplified) [f]_
|| image | deltB.jpg | 90
Deformations - Longitudinal Seismic (visually amplified) [f]_
|| text | cp_echo.txt | literal
|| text | cp_str.txt | literal
|| text | cp_eig.txt | literal
|| text | cp_str.txt | literal
""")
#! python
# %%
import rivtlib.rv_lib as rv
rv.D("dev", "default", "Code Minimums - Carport Renovations", "21")
# %%
rv.I("""[01] Structural Deficiencies
The carport is a post and beam structure that was connected primarily by
gravity and friction and a few nails and screws with minimal capacity.
In addition there was significant post decay. Initially the posts were
supported on spread footings and the parking area was gravel. At some point
a few decades ago, the posts were encapsulated with a concrete slab up to 8
or 9 inches to provide a better parking surface. The encapsulating concrete
trapped water around the columns bases which caused serious decay and
eventually led to partial column failure, 90% section loss in some cases
and differential settlement up to 7 inches.
|| image | carport01.jpg | 90
Carport [f]_
""")
rv.I("""[02] Carport Repairs and Strengthening
Beam to beam, post to beam and brace to beam and post connections were
strengthened with 1/8" galvanized angles or plates that were attached with
lag bolts or galvanized threaded rods or bolts.
The carport was shored and leveled, the decayed bottom of the posts were
# %%
import rivtlib.rv_lib as rv
rv.D("pdf", "default", "Carport Wind Model", "1")
rv.I("""[01] Carport Unit Loads and Weight
Roof unit dead loads [t]_
[literal]_
========== ======= ========= =================================
variable value [value] description
========== ======= ========= =================================
ld1 2.0 psf 0.096 KPa Urethane foam (4 inch thick)
ld2 1.0 psf 0.048 KPa Three-ply roofing
ld3 5.0 psf 0.239 KPa Doug Fir decking 2-in.
ld4 1.0 psf 0.048 KPa Doug Fir beams 4x12 at 12 ft o.c.
========== ======= ========= =================================
""")
rv.V(""" Carport Weight
Carport Geometry [t]_
cp_width = 22.75 | FT,M | carport width
cp_length = 19.5 | FT,M | carport length
roofdl1 = 9.0 | PSF, KPA | unit load
Weight of carport [e]_
cp_wt = cp_width * cp_length * .009*KSF | KIPS, KN
""")
rv.I("""[02]_ Background
The structural calculations address remodeling, repair and strengthening of
a single family residence.
The single family residence dates to the 1940's and was built on two
combined lots with an average grade of about 1 in 6. It has a reinforced
concrete strip foundation, under house storage, plywood sheathed perimeter
walls, and a flat T&G plank roof (under an original tar and gravel membrane
overlaid with foam) supported by interior posts and beams. The car port
structure is also a post and beam structure with roof planks.
During the prior decades the carport posts had significantly decayed below
the slab line, leading to uneven carport roof settlement up to 6 inches. In
addition surface sliding had piled soil up to a foot deep causing the lower
part of the siding to decay. Decayed portions were removed and replaced and
a planter/retaining structure was designed to retain the sliding and
prevent further decay.
The residence foundation was seismically vulnerable. Two sides of the floor
diaphragm were directly supported on the strip foundation but the other two
sides were supported on stud walls up to 6 feet tall. The framed foundation
walls had very little in-plane strength which made the entire structure
vulnerable to earthquake damage from first floor twisting. Each of the two
framed walls had a single minimal compression brace that could not
prevent seismic translation. Four new shear walls were added.
In summary, over the course of the last five years work was done to
mitigate safety hazards including seismic vulnerabilities and wood decay,
and improve living spaces.
|| table | project_area.xlsx | 60,L | [2,1,3]
|| image | house01.jpg | 60
Residence viewed from Loring Drive [f]_
""")
#! python
# %%
import rivtlib.rv_lib as rv
rv.D("dev", "default", "Loads - Residence Renovations", "9")
# %%
# %%
rv.I("""[01]_ Load Combinations
Basic loads and load combinations are derived from the California Building
and Residential Codes.
|| table | load_types01.csv | 30,L | [:]
|| table | asce7_load_comb.csv | 55,C | [:]
[page]_
""")
# %%
rv.V("""[02]_ Gravity Loads and Seismic Mass
|| config | nosub | 2,2
Roof unit dead loads [t]_
|| value | dlroof0.csv
Floor unit dead loads [t]_
|| value | dlfloor0.csv
rv.I("""[01] Minimum Wall Sheathing CRC - First Floor
The residence is sheathed in exterior 1/2" 5-ply plywood nailed with 8d
common nails at 12" oc at edges and field. The boundary nailing capacity is
half of the maximum spacing tabulated in the building codes. The residence
is checked against the CRC prescriptive wall opening limits, assuming 6" oc
(which is not the case) to assess the degree of wall continuity. A CBC
analysis is performed in calculation 0301 which estimates the DC ratios for
the 12" oc nailing.
|| image | mv_nail1a.jpg, mv_nail2a.jpg |40,56
Existing shear wall nailing - 8d at 12" OC [f]_
Existing shear wall nailing - 8d - 2-1/2" penetration [f]_
The minimum solid wall percent is given in the following CRC table.
|| table | r602_3wallpercent.csv | 15,C | [:]
The percent solid wall for each shear wall is:
|| table | solid_shearwall.csv | 15,R | [:]
**Therefore, if edge nailing requirements are met the residence meets the
prescriptive opening requirements of the CRC.**
|| image | shearwalls1d.jpg | 90
First floor shear walls - north and west sides [f]_
|| image | shearwalls2d.jpg | 90
First floor shear walls - south and east sides [f]_
[page]_
Check required basic fastener spacing:
|| table | r602_3fasten.csv | 30,L | [:]
|| text | r602_3fasten_notes.txt | literal
Check code required wind governed fastener spacing:
|| table | r602_3wind.csv | 30,C | [:]
|| text | r602_3wind_notes.txt | literal
**In order to meet the code prescriptive wind and seismic requirements the
number of nails at the exterior sheathing panel boundaries need to be
doubled - from 12" oc to 6" oc. Refer to CBC analysis in calculation 0301
for an analysis of DC ratios with reduced capacity**
""")