Cableway Safety and Inspection Common Cableway Problems

Common Problems Loose backstays & main cable sag issues A-frame towers Footing/pedestal connections to A-frame Mass anchors and U-bars Freeboard Hardware Streambank erosion & slope stability Design and as-built documentation

Loose backstay cables

Main Cable Sag

Systems designed to current standards should use sag curve from Streamgaging Cableways (Note: not a 2% sag at all points on curves) Older systems should use sag curve from Circular 17 (Pierce, 1947), presented in Streamgaging Cableways 3% sag line

A-frame towers

Saddle Blocks

Sheaves/Saddle Blocks Strength Efficiency - Bending wire rope reduces its strength. To account for the effect of bend radius on wire rope strength when selecting a sheave or saddle block, use the table below: D/d ratio should be > 10 (Streamgaging Cableways) D/d ratio for a pipe A-frame and 1” cable is approximately 6 (not within USGS standards) Ratio D/d Strength Efficiency Compared to Catalog Strength in % D: diameter of sheave, saddle block, etc. d: diameter of main cable

Cable Cars

Cable Cars HIF Cars –Retrofits are required on all stand-up cars (Nov 1997) (Retrofit kits are available from the HIF; part # ) –Retrofits are required on all sit-down cars (Sept 2002) (Retrofit kits are available from the HIF; part # )

Freeboard Design Water Surface Freeboard unknown or documentation lacking Not enough freeboard at 100-yr flood stage Reference mark needed to indicate maximum stage for safe measurements

Footing/pedestal connections to A-frame tower

Footing/pedestal connections to A-frame tower

Footing/pedestal connections to A-frame tower A+

Mass Anchors and U-bars Mass anchors –Many are undersized or actual dimensions unknown –Submergence –Below grade causing cable to lay on ground U-bars –Many are undersized, oriented incorrectly, poorly aligned, or placed at wrong angle –Often no auxiliary U-bars –Use quality U-bars

Mass Anchors Undersized Dimensions unknown Poor below-grade construction Built flush or below grade U-bars Undersized Bearing blocks Poorly aligned Auxiliary U-bars Quality steel?

Mass Anchors & U-bars

Mass anchors & U-bars

Mass Anchors & U-bars

Mass Anchors & U-bars

Standard Anchor Setup Main U-bar and turnbuckle sized to meet specs Two auxiliary U-bars sized to meet specs (see Streamgaging Cableways for details on specifications for sizes and number of main and auxiliary U-bars)

Hardware Eyebolts Clips Thimbles Shackles

Eyebolts Forged, shoulder-type bolt Bolts must be sized to meet load (1” minimum; Streamgaging Cableways) ONLY 30% efficient at 45° angle!!! Table 1 (In - Line Load) Size (in.) Working Load Limit (lbs.) 1/4650 5/161,200 3/81,550 1/22,600 5/85,200 3/47,200 7/810, , /421, /224,000

Failed Eyebolts Not shouldered; not forged Eye is welded shut Long shank; eye should be flush to bearing plate Undersized Placed horizontal not vertical Not-shouldered; not-forged Eye was welded to bolt Undersized (*** This eyebolt failed during a load test before reaching the 2,250 lb design load)

Clips & Thimbles Thimble undersized Clip too far from thimble Good

Clips Clips should be installed with saddle on “live” end of cable as shown: NEVER reuse clips; throw old clips away!!! What if clips have been installed the wrong way? –Leave original clips in place; install new clips, in the correct direction, in the spaces between the original clips –Or if possible; remove clips, cut off “used” portion of cable and install new clips according to manufacturers directions (see Streamgaging Cableways)

Clips-continued When installing new clips on a new cable: –Follow instructions in Streamgaging Cableways Install first (one base width from end) and last (as close to the loop as possible) clips and then install remaining clips equally spaced between the first two No standard spacing between clips; depends on turnback length –Re-torque after first use and again after any larger than normal loads have been placed on the system –If there is a need or you want to check torque during annual inspections, set torque wrench to one setting less than the required torque

Other Hardware Poor Seizing at Ends Sockets

Streambank Erosion

Pre-runoff Post-runoff

Streambank Erosion

Slope Stability

Maintenance Paints & Coatings Special Inspections Unexpected Events

Design and As-Built Documentation (Items Frequently Lacking) Mill certificates & material certifications Make & model numbers of hardware Receipts or design-file notes Subsurface anchor and pedestal dimensions Details of steel reinforcement used Type of cement used in concrete mix As-built drawings or sketches

Did cableway pass inspection? Yes? No? Maybe? Knowledge, judgment, communication