make summary for each lucture

lecture_25_11-15.pdf

Home >Reading homework help >make summary for each lucture

HURRICANE MITIGATION Ø  Strengthen vulnerable doors such as reinforcing with slide bolts (especially inward swinging entry doors and old-style sliding doors)

Ø  When pu;ng new doors, use doors with Miami-Dade County NOA Ø  Plan for safety exists from your shuFered house Ø  Reinforce garage doors using braces (or use shuFers); strengthen

both the track and the door itself [80% of damage to residenNal homes stars with a garage door failure]

Ø  ShuFer or reinforce sliding glass doors [lip at boFom reduces WDR]

HURRICANE MITIGATION Shu1ers vs. Impact Windows Ø  ShuFer Pros: less expensive, easy to replace, reduces water leakage Ø  ShuFer Cons: needs to be put up, unaFracNve, require maintenance,

does not reduce wind pressure [In some jurisdicNons you must get a permit to install shuFers which is a Good Thing; in many areas plywood shuFers are technically illegal] Ø  Impact Window Pros: no hassle to put up, no maintenance, protects

against debris and wind pressure Ø  Impact Window Cons: more expensive, expensive replacement [You may use window film on windows on upper floors of high rises which might only need to be strengthened, not protected from debris]

12-FAN WOW SHUTTER TESTING

Interior side of window aGer WDR tesIng with window protected by shu1er

Interior side of window aGer WDR tesIng with window NOT protected by shu1er

•  12-fan WOW tests showed that unprotected window can cause significant water intrusion as compared to window protected by shu1er. The observaIons confirm the ability of the shu1er system to significantly minimize water intrusion through a window. This can have implicaIons on loss modelling which generally doesn’t account for reducIon of water intrusion through window systems that are protected by shu1ers.

•  Shu1er does not have a significant effect on reducing wind loads on the window. Such

loading can cause failure during high wind events such as hurricanes. However, the net pressures on the shu1er itself show significantly low values because of the pressure equalizaIon between the exterior surface pressure on the shu1er and the pressure in the cavity between the window and the shu1er.

12-FAN WOW SHUTTER TESTING

HURRICANE MITIGATION 2. Strengthen roof sheathing and roof covering a3achments Understanding Roof Aerodynamics

•  Moderately pitched hip roofs, where there is no gable, are the best style for hurricane zones. [high sucNon can occur in hip Nles though]

•  Highest sucNon occurs on roof edges and corners •  Flat roofs are the worst in terms of aerodynamics •  Gable roofs are also poor aerodynamically •  Internal pressure due to breached openings can overpressurize roofs

WOW studies on Wind Pressure DistribuIon on Gable and Hip Roofs: Study of the interacIon of winds with roofs to determine the types of pressures affecIng them and their distribuIon.

HURRICANE MITIGATION Ø  Use plywood not OSB for sheathing Only plywood should be used as roof sheathing. Oriented Strand Board (OSB, a strong kind og parNcle board) doesn’t perform as well and is not allowed in HVHZ (see FBC) Ø  Use ring-shank nails to secure roof sheathing “The proposed modificaNon calls for the 8d ring-shank nail to become the standard roof- sheathing nail in the High Velocity Hurricane Zone of Florida. Research carried out by the IHRC during 2003 has shown the ring-shank nail improves the performance of a roof under hurricane uplie loads by a factor of up to 130% without increasing the cost of construcNon.” hFp://wamp.ihrc.fiu.edu/wp-content/uploads/2012/05/HLMP_Year04_Quarterly1.pdf

HURRICANE MITIGATION Ø  Use proper nail spacing for edge and field zones Ring shank nails with 6” spacing for edges and corners (and may be 12” spacing for field zones) to connect sheathing to the raeers (FBC). Staples too oeen miss the wood below. “Head pull-through failures can also contribute to or control the ulNmate uplie capacity of roof panel connecNons. This failure is commonly observed when ring-shank nails or screws were used to aFach nominal 1/2-inch plywood and oriented strand board (OSB). However, these panel tests found head pull-through failures were extremely rare for 5/8-inch (actual 19/32 inch) sheathing, even when ring-shank nails were used, supporNng the suggesNon that this thickness is a good choice in high-wind areas. Through this research, we can conclusively say that 8d ring-shank nails installed at 6-inch spacing over the enNre roof nearly doubles the uplie capacity of 5/8-inch roof sheathing compared with panels aFached with 8d common bright or 8d galvanized nails.” Dr. Tim Reinhold -- January/February 2006 CoastalContractor

HURRICANE MITIGATION Ø  Use roof Nles with NOA and use proper aFachment methods Miami-Dade County modified the rules for holding Nles to the roof aeer Hurricane Wilma •  Eliminate the mortar set opIon for hip and ridge Ile.

•  Require specific post installaIon tesIng of hip and ridge cap installaIon by third party tesIng agencies.

•  Require Ile clip be installed along with the other required Ile fasteners on each Ile along the first course for mechanically a1ached roof Ile systems.

•  Three prescripIve a1achment methods for ridge and hip Iles (later tested at FIU WOW)

12-FAN WOW IMPORTANT RESEARCH AREA Effects of Corner Vor;ces and Resul;ng Suc;on Varia;ons on Roof Need to be Incorporated in Test Protocols

suction variation under vortex

12-FAN WOW FULL-SCALE ROOF TILE TESTING

0 5 10 15 20 25 30 35 40 0

TILE -T5 AOA = 150o

TILE -T9 AOA = 60o

TILE -T11 AOA = 0o

-1.1

-1

-0.9

-0.8

-0.7

-0.6

-0.5

-0.4

12-FAN WOW FULL-SCALE ROOF TILE TESTING Performance of various types of code prescripIve Ile a1achment methods was evaluated. •  Failures of eave and gable-end Iles were observed for mechanical and single-paddy Ile

a1achment, respecIvely.

•  The failure of gable-end Ile was due to the insufficiency of the a1achment in resisIng high sucIon wind pressure on the gable-end Ile.

•  The failure of eave-Ile despite the low pressure coefficient indicated that failure could be a1ributed to high vibraIon of the enIre Ile roof system under upliGing force.

•  Among all the three systems tested, the double paddy Ile roof system performed best based on the angle of a1ack tested.

12-FAN WOW TILE ATTACHMENTS TESTING

12-FAN WOW USE OF TEST DATA ON TILES •  Monte Carlo simulaIon of vulnerability

curves showed that including the cavity internal pressure results in an overall increase in Ile damage from upliG.

•  The implicaIons of the loss of Ile roof cover go well beyond the cost of Ile replacement, and include increased vulnerability to rainwater ingress.

•  The findings are significant with regard to loss modeling, installaIon pracIce, miIgaIon policy.

HURRICANE MITIGATION 2. Strengthen roof sheathing and roof covering a3achments Ø  Use approved asphalt shingles

•  Heavy duty Miami-Dade County approved shingles should be used

•  Proper installaIon technique needed •  Proper curing and sealing is of utmost importance

Current WOW Research on Wind Effects on Shingle Roofs ObjecIve: Recommend ways to incorporate effects of cornering winds in ASTM and TAS test methods; InvesIgate the applicaIon of shingles to roofs with mean roof height > 33 G.

12-FAN WOW SHINGLE TESTING

UF/IBHS SHINGLE TESTING

DISSERTATION: THE WIND RESISTANCE OF ASPHALT ROOFING SHINGLES by CRAIG ROBERT DIXON (University of Florida)

UF/IBHS SHINGLE TESTING

Diagonal installaIon of three-tab asphalt shingle system

UF/IBHS SHINGLE TESTING

Location of sealant strip relative to the shingle’s leading edge and fasteners

Plan view of a standard three-tab shingle with six fastener locations shown

UF/IBHS SHINGLE TESTING

Partial unsealing for three-tab shingle Blown off three-tab asphalt shingles

UF/IBHS SHINGLE TESTING

UF/IBHS SHINGLE TESTING •  ParIally unsealed shingles installed in the field, hip and ridge locaIons of the roof

contribute significantly to the wind damage of asphalt shingle roofs. The cause of parIally unsealed shingles in the field of the roof was not fully idenIfied; though, long-term weathering effects, as opposed to wind, are the likely cause.

•  Wind test results showed that all damage in the field of the roof iniIated from shingles that were found unsealed prior to the wind test or liGed shingles at eave and rake roof locaIons. Fully sealed shingles remained fully sealed and undamaged in all tests, unless damaged by

adjacent pre-wind unsealed or liGed eave and rake shingles. Damage to the pre-wind unsealed shingles consisted of blow off, folding, and tearing.

•  Retrofit techniques for unsealed field, hip, and ridge shingles are given in FEMA P-499 (2012). The technique involves the applicaIon of asphalt roofing cement in 25 mm (1 in) dollops along the leading edges of unsealed asphalt shingles. Large-scale implementaIon is quesIoned due to known blistering effects when excessive applicaIon occurs.

HURRICANE MITIGATION 3. Improve roof paver design and metal roof design Ø  Use paver interlocking systems •  Use straps to distribute upliG •  Do not a1ach parapets to paver systems

Ø  Use favorable aerodynamic design for seams and edges •  VerIcal seam versus trapezoidal seam for reducing vibraIons •  Avoid seams at edges (more research undergoing) •  Reduce seam spacing (more research undergoing) Current WOW Research on Wind Effects on Standing Seam Metal Roofs ObjecIve: Compare WOW test results with those of the ASTM/UL test methodology; Recommend improved deflecIon and loading criteria. [The shape and spacing of standing seams have been found to significantly affect the wind pressures on roof.]

12-FAN WOW TESTING OF ROOF PAVERS

Effect of Pressure Tap Layout on External Cpmean (hp/H= 0.05 and G/ Hs= 0.25)

12-FAN WOW TESTING OF ROOF PAVERS

12-FAN WOW STANDING SEAM METAL ROOF

Vertical-Leg Standing Seam Roof Trapezoidal Standing Seam Roof

12-FAN WOW STANDING SEAM METAL ROOF Peak Pressure Coefficient, Cp,peak Comparison

12-FAN WOW STANDING SEAM METAL ROOF

UNIFORM PRESSURE TEST VIDEO