Bridge Mitigation 2018 NATIONAL HURRICANE CONFERENCE WORKSHOP - PowerPoint PPT Presentation

Replace Truss Style with Open Deck  Problem:  For bridge crossing that experiences occasion flooding/over topping, a steel truss bridge tends to create conveyance problems, especially if trapped with debris.  Solution:  Replace steel trust bridge with open deck style. This reduces forcing acting on bridge during flooding/over topping. It also reduces entrapment of debris.

Replace Multiple Span with Single Span  To further enhance flow character:  The addition of shaping and covering of embankment  Use of wing walls along abutments  Smooth alignment of channel and bridge abutment

Replace Multiple Span with Single Span  Effectiveness:  Limitation:  Very effective in most  Physical limitation of application how long a single span  Greatly increase bridge can be used. flood profile/opening  Greatly reduces debris accumulation. 40

Salt Damage Common Repairs  The use of chloride deicing salt has become the single most important element in repairs and maintenance of bridge decking. Salt encrusted bridge

Salt Damage Common Repairs  Common Repair Solution  Economic solution includes patching of individual potholes, to complete re-surfacing of bridge decking.  However, this is just a temporary, as a permanent solution is to repair the damaged concrete. This includes provide an impervious sealing of deck to halt salt intrusion.

Salt Damage Common Repairs  Effectiveness:  Limitation:  Usually does not stop  Quickly allows surface corrosion repairs using low  Eventually, funding is funding. needed for full deck replacement. 43

Seismic Retrofit  Modification of bridge structure to make them more robustly  Problem (what are solutions?)  Soft Rivets:  Bridge Attachments:  Suspension Bridges Decks  Lattice beams, girders, bridge ties

Sudden High Load Failures  Solution to prevent bridge failures from sudden high loads.  Concrete bridge piers can fail from earthquakes, from wind load from tornadoes/hurricanes, from collisions with ships, vehicles, etc. Waves and winds can displace bridge spans or totally collapse of spans. It can result in destruction of concrete decks and pre-stressed beams due to uplifting, etc. Railways can be washed away from bridges.

Sudden High Load Failures  Solution:  Precast/pre-stressed bridge pier caps and girders, instead of casting on site.  Reinforced steel and concrete tie-ins between bridge decks and pier caps.  Higher/taller span can clear large storm surge.  Use of guard rails (check rails) on bridges.  Increase number of piers  Enforce weight limits, including maintenance equipment and re-paving.  Use of isolation bearings

Suicide Prevention  Many high bridges become a draw for people attempting suicide.  Solution: Some solution includes a barrier

Suicide Prevention  Effectiveness:  Limitation:  Effective in stopping  Usually very expensive suicides from the bridge  Tends to be itself, but also suicide aesthetically unsightly, rate in surrounding detracting from the area. appearance of the  Prevent injury to traffic bridge, and view from and people below the bridge. bridge  Poorly designed barrier can affect bridge structural integrity, especially during high velocity wind 48

Structural Monitoring  Monitoring should include:  Crack growth/creep in concrete structural member  Rotation of piers in water bodies, as a result of scouring.  Span expansion joint displacement as a result of hot/cold cycling  Fatigue cycling measurement  Vehicle weight overload monitoring/enforcement  Monitoring can be performed wireless, which allows remote display of data.

Structural Monitoring  Effectiveness:  Limitation:  Effectively reduces  Lack of internal abilities overall maintenance cost by avoiding problems  Help avoid catastrophic failure of structure and loss of lives  Helps in development of more accurate budgeting, reducing long term costs 50

Bridge – Truss Bridges Mitigation  Problems with Truss Bridges  Require considerable amount of space (this creates problems that often result in accidents)  Are relatively heavy, costly, time consuming, require lots of upkeep.  Wasteful. If not correctly designed, it may waste material (element may have no useable function).  Low level of redundancy

Bridge – Truss Bridges Mitigation  Many consider it a durable and strong style of bridge that have been used since the middle of the 19 th century.  Truss bridges are candidates for catastrophic failure when gusset plates fail.  Solution  External post-tensioning using high-strength cables or bars.  Use modern bridge modeling to re-check design and capacity of truss bridge.

Bridge – Truss Bridges Mitigation  Effectiveness:  Limitation:  Reduces chance for  Lack of Information massive catastrophic  Lack of guideline failure  More cost effective than replacement of bridge  Increases life span of bridge  Effective and economical  Speed of construction and minimal disruption of traffic . 53

Epoxy Asphalt Polymer  Epoxy Asphalt Concrete is an excellent choice for durable bridge road surface, with over 45 years of proof.  Other features:  Surface is highly impervious, which reduces underlying steel deck corrosion  Ability to bond, and stay bonded at elevated surface temperature  Long lasting and elastic  Can be used as thin overlay when weight is limiting factor  Traffic can resume within 2 to 4 hours (for light traffic condition)

Epoxy Asphalt Polymer  Other features  The two-phase Epoxy Asphalt binder is a thermoset polymer:

Epoxy Asphalt Polymer  Effectiveness:  Limitation:  Low maintenance  Lack of industry-wide knowledge of its use  Reduce loading  Higher initial cost 56

Fly Ash  Use of fly ash in concrete mix, improve installation and performance near coastal area.  Many mixture available  Improve performance of structure.

Bridge – Fly Ash

Fly Ash  Fly ash is one of the residues generated in combustion, and comprises the fine particles that rise with the flue gases.  Fly ash includes substantial amounts of silicon dioxide (SiO 2 ) (both amorphous and crystalline) and calcium oxide (CaO), both being endemic ingredients in many coal-bearing rock strata.

Fly Ash  Effectiveness:  Moderate heat gain during curing  Provides sulfide and sulfate resistance, especially in soil use  Provide superior /more durable finished concrete (qualify as durable material); more predictable and consistence finish

Fly Ash  Effectiveness:  Ensure faster construction.  Produces high strength  Lower maintenance concrete for use in thinner sections  Flexibility accommodates curves, arches, and other architectural shape.  Improves flowability, which less wear, expense, tear of equipment. 61

Bridge – Fly Ash  Limitation:  Lack of industry wide knowledge of its use  Problem with heat dissipation, especially in tropical area.  Increases time need to reach full strength  Longer setting time  More susceptible to cold temperature,

Concrete – High Performance/High Strength  High Performance Concrete (HPC) is a recent new term.  HPC is concrete that perform above common industrial grade concrete.  But this is not necessarily limited to strength alone.  Put in another way, all high-strength concrete is automatically high performance, but the converse is not always true….not all HPC is high -strength.

Concrete – High Performance/High Strength  What makes high-strength concrete?  Mineral admixture  Chemical admixture  Reduce weight requirement

Concrete – High Performance/High Strength  A common use at present is also for lighter weight, simpler, stronger bridges.  A large portion of the design of a bridge is to simply be able to support its own weight alone .

Concrete – High Performance/High Strength  Effectiveness:  Limitation:  Lighter weight, simpler,  Higher initial material stronger bridges cost.  Longer span, fewer piers  More extensive architectural/engineer  Replace heavy concrete development/planning decking with lighter, high performance concrete, steel, thus increasing bridge lifespan, and increasing traffic capacity. 66

Culvert - Arched  The cost would be a small fraction of the cost to rebuild structural steel bridge.  Design effort and cost would be minimized to determining hydrologic and hydraulic flow requirement.  Fill above arched culvert would allow simple paved roadway to be installed.

Culvert - Arched  Pipe culverts, in comparison, have higher maintenance and beaver activity.  This is seldom a problem with properly sized arched culvert.  Pipe culverts tend to have higher plugging from debris and blow outs, especially if undersized.  Replacement may be recurring problem.  Again, this is seldom a problem for properly sized arched culverts.

Culvert - Arched  Effectiveness:  Maintain stream flow to natural width and flow  Substantial lower cost condition (as opposed than structural steel to possible hung bridge culverts with standard  Greater design time and pipe configuration – effort culverts hanging above  More cost effective for water line). span greater than 13 feet, compare to pipe culvert. 69

Culvert - Arched  Limitation:  May be barrier to movement of large woody debris  Should not be used where foundation is questionable  Footing must be protected from scouring and subsurface flows.  Should never be constructed on existing fill  Can catastrophically fail if flow overtop road and fill is washed away or if scouring takes out footing or causes undermining.  Higher upfront installation cost compared to pipe culvert, but greatly reduced future maintenance cost, especially cost to maintain culvert in place.

Culvert - Railroad Stainless Steel Tank Car Culvert Bridges  An alternative is the use of salvaged stainless steel tank railcar.  Tank cars are shipped to location, as part of a train.  At the site, the tank cars are uncoupled and lifted off the rails.  The railcar trunks and coupling are removed.  The ends of the tank are torched off.  The tank is used just like any other culvert, usually trunked to the replacement site.  The tank walls are so strong and thick, that they normally do not have reinforcement, such as ribs, frames, etc.

Culvert - Railroad Stainless Steel Tank Car Culvert Bridges   Limitation: Effectiveness:  No maintenance – will  Limited sizes. withstand corrosive soil  Cost effective – cost is less than CMP and last a lifetime  Not damaged by flooding. If one is dislodged, it usually not damaged or flatten. Just reinstall.  Flow 30 to 40% more than same diameter RCP or CMP. 72

Culvert Relief  Bridge subject to periodic stream flooding that overtop bridge, washing out structure. Culverts placement under Highway Bridge to prevent overtopping of bridge

Culvert Relief  An alternate is a costly straightening of the stream channel that includes extensive concrete embankment.  Lost-cost mitigative solution was the installation of a culvert across the curving floodplain, under the approach to the bridge.

Culvert Relief  Effectiveness:  Limitation:  Comparably lower cost  Bridge designer not and very effective. familiar with effects/manipulation of  Lower regulatory streams requirement  Minimal environmental foot prints 75

Debris Sweeper

Debris Sweeper  Current induced rotating debris sweeper: A solution to drift induced scour

Debris Sweeper  The debris sweeper is attached to a tracking system, which mounts on a bridge pier or box culvert diaphragm wall.

Debris Sweeper  Debris sweeper are installed in hundreds of locations in Alabama, California, Louisiana, Oklahoma, Ohio, Oregon, Virginia, Washington.  The debris sweeper provides enhanced rotation for flat to steep slope conditions by virtue of its computer generated fin design and polyethylene construction.  Debris sweeper is a real solution to interrupting the cycle of drift removal, and a respite in maintenance due to drift accumulation.

Debris Sweeper  Effectiveness:  Limitation:  Low maintenance  Proper Installation  Cost effective  Small MUC  Not damaged by fast  Not intended for moving missiles, such as large ships or logs barges . 80

Geotextile Filter Fabric  Geotextile filter fabric is a permeable textile material that increases stability of underlying soil, provide for erosion protection, increase drainage.

GPS Locations of Bridge Towers/Piers  First efforts should be made to ensure Global Positioning System ( GPS ) location of piers and towers in navigable waters be uploaded into databases of major GPS manufacturers, especially for maritime use.  Recommend collision alarm be incorporated, just as GPS alert of street intersection with traffic cameras and collision with merchant vessel.

GPS Locations of Bridge Towers/Piers  Effectiveness:  Limitation:  Effective under low  GPS users do not visibility or night use. frequently update their GPS database. 83

Jersey Barrier

Jersey Barrier  Jersey Barrier  K-Rail  a rigid, tapered modular concrete barrier used to separate lanes of traffic traveling in opposite direction.  Its architectural design is such that, it controls/focuses the energy of a vehicle striking it.  It prevents crossover of head-on collision.

Jersey Barrier  Jersey Barrier on Bridges  An important use is retrofitting of existing bridges  prevent major damages to bridge infrastructure that could result in • catastrophic failure, • major repair cost of bridges.

Jersey Barrier  Jersey Barrier  A typical Jersey barrier stands 32 inches (81 cm) tall  made of steel-reinforced poured concrete  designed to safely deflect vehicle energy away from the bridge, especially extremely heavy out-of-control semi- trucks.  It starts with the first 2 inches from pavement rises vertically, next 10 inches rises at 55 degree angle, then remainder at 84 degree.

Jersey Barrier  Effectiveness:  Effective for small vehicles to gasoline laden tanker semi  Greatly reduces kinetic/potential energy from being transferred to bridge infrastructure, thus greatly reducing damaging effects of all collision.  Relatively easy to retrofit to existing bridge structure.  Does not significantly increase weight loading of bridge..

Jersey Barrier  Effectiveness:  Additional benefit of restraining vehicles from crashing off side of bridge and falling into roadway, river or railroad below. It prevents semi, buses, pedestrians and cyclist from vaulting or rolling over barrier.  Limitation:  May not be practical to retrofit small, narrow bridges.  May increase chance of vehicle roll over, if barrier is not smoothly finished.

Railroad – Wood versus Concrete Ties  Wood rail ties  The standard choice, even today.  When chemically impregnated, they have a relatively long life.  They can be used on almost any type of bridge, since the spikes are hammered into ties, they can be used anywhere.  However, they are still susceptible to rot, physical damages, and fire from fuel oil soaked from locomotive dripping.  They have 20-30 life span

Railroad – Wood versus Concrete Ties  Concrete Ties  Use is growing,  more rigid than wooden, and will never rot.  designed to expand and contract in unison with the welded railed they braced.  They should have a life span exceeding 50 years with no failures

Railroad – Wood versus Concrete Ties  So why go with concrete?  They allow for high track speed because they do not need periodic maintenance like wood.  Because the track is more rigid, locomotive uses less fuel to pull across the bridge.  Wood only has an advantage of costing 35% less, but that’s only for initial cost. • In the long run, wood costs significant more than concrete in overall cost and maintenance. • Wood ties cost $28 each, versus $41 for each concrete tie.

Railroad – Wood versus Concrete Ties  Effectiveness:  Significant longer life  Wooden ties may eventually be outlaw, thus forcing massive replacement with concrete.  Stop maintenance work on tracks, which will result in structural impact on bridge, especially from heavy weight from maintenance equipment. While concrete ties are heavier, the much greater impact is from maintenance equipment.

Railroad – Wood versus Concrete Ties  Limitation  Require custom hardware to hold rail to ties.  Require machinery to be adjusted or layer.  Initially more expensive  Need proper air entrainment (5-7%) for freeze-thaw resistance

Stopping of Bridge Stay/Suspension Cable Galloping  Tuned Mass Dampener

Stopping of Bridge Stay/Suspension Cable Galloping 1-loop galloping Static span position amplitude of motion

Stopping of Bridge Stay/Suspension Cable Galloping 2-loop galloping amplitude of motion Center of span

Stopping of Bridge Stay/Suspension Cable Galloping 3-loop galloping Nodes at 1/3 & 2/3 span amplitude of motion

Stopping of Bridge Stay/Suspension Cable Galloping  Vast human ingenuity has been devoted to the problem of damping or eliminating this vibration, to protect the cable. This vibration can damage stays, cable and other connected parts.

Stopping of Bridge Stay/Suspension Cable Galloping  Dog bones should be added at time of new construction.  However, they can be added later, even if the cables are installed.  This makes for a relatively inexpensive retrofit and mitigation,  the bridge maintenance staff can install them while the bridge is in active use.

Stopping of Bridge Stay/Suspension Cable Galloping  Spiral Vibration Damper  For smaller cable, a different dampener can be used, which is more effective than the Stockbridge style for this application.  The spiral Vibration Damper has been successful for over three decades to control vibration induced by the wind for smaller sizes of cable and wire.

Stopping of Bridge Stay/Suspension Cable Galloping  Effectiveness:  Very effective and economical  De facto standard of major electrical utility, especially for transmission and feeder line  Easy to install  Can be retrofitted with bridge in service.  Can be installed well after a cable has been installed or repaired  Limitation:  Many bridge engineers are not aware of this technology

Bridge – FIU Sweetwater University City Pedestrian Bridge 103