Bridge Load Rating Manual

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Date 06-05-19 Structure Number Request Form Excel XLSM - 35 KB, Rev. Date 09-17-19 DOCUMENTS ARCHIVE 1982 Load Rating Manual Adobe PDF - 24.3 MB, Rev. Date 09-01-82 1995 Load Rating Manual Adobe PDF - 2.4 MB, Rev. Date 03-16-95 2006 Load Rating Manual Adobe PDF - 171 KB, Rev. Date 10-19-06 2009 Load Rating Memo, Double-Leaf Bascules Adobe PDF - 119 KB, Rev. Date 08-19-09 2010 Load Rating Memo, Striped Lanes - Segmentals Adobe PDF - 271 KB, Rev. Date 04-06-10 2011 Load Rating Manual Adobe PDF - 933 KB, Rev. Date 01-01-11 2011 Load Rating Memo, Redacts FL120 Service III Adobe PDF - 141 KB, Rev. Date 09-01-11 2012 Load Rating Manual Adobe PDF - 1.4 MB, Rev. Date 08-01-12 2014 Load Rating Manual Adobe PDF - 891 KB - Rev. Date 01-01-14 2014 Load Rating Summary Form - LFR Excel XLSX - 32 KB, Rev. Date 01-01-14 2014 Load Rating Summary Form - LRFR Excel XLSX - 32 KB - Rev. Date 01-01-14 2015 Load Rating Manual Adobe PDF - 1.3 MB - Rev. Date 07-13-15 2015 Load Rating Summary Form Excel XLSX - 538 KB, Rev. Date 07-13-15 2016 Load Rating Manual Adobe PDF - 750 KB - Rev. Date 09-26-16 2016 Load Rating Summary Form Excel XLSX - 540 KB - Rev. Date 09-26-16 2017 Load Rating Manual Adobe PDF - 2 MB - Rev. Date 02-20-17 2018 Load Rating Manual Adobe PDF - 1.77 MB - Rev. Date 12-22-17 2018 Load Rating Summary Form Excel XLSX - 548 KB - Rev. Date 12-22-17 2018 Load Rating Summary Form with Emergency Vehicles Excel XLSX - 535 KB - Rev. Date 10-08-18 2019 Load Rating Manual Adobe PDF - 1.79 MB - Rev. Date 10-11-19 2019 Load Rating Summary Form Excel XLSX - 532 KB - Rev. Does this confirmation only seek to show that the operating truck, placed at the ordinates shown in the table, meets shear and moment criteria in the underlying beams? If more is expected, please clarify. At a minimum, confirmation of the governing HS20 or HL93 Operating Rating; show the factored components of the rating factor equation. http://www.gwardiajuvenia.pl/zdjecia/fck/brother-mfc490cw-user-manual.xml

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A more comprehensive check is recommended, especially when results significantly differ from the original Design Load increased to the Operating Level. It is helpful to show the internal components as well, the factorsThe intent is to (1) provide a starting point for review, and (2) show that the analyst can readily identify the critical components, that the work is more than “button pushing.” Furthermore, a widening need not assess EVs either, if the rating methodology is LRFR and the results meet minimum strength criteria outlined within SDG Chapter 7. EV analysis for segmental bridges may be based upon the existing load rating, and amended to include EV ratings. If other posting avoidance techniques are unsuccessful, then try the most difficult posting avoidance. With the associated multiple presence factors, take the worst of:However load ratings need not apply postingThat is, it is not necessary to doggedly exhaust a maze of regulations before concluding with a path that was known at the outset. Submit a question or comment concerning Bridge Load Rating by clicking here. Submit a question or comment concerning this website by clicking here. If you do not want your E-mail address released in response to a public records request, do not send electronic mail to this entity. Instead, contact this office by phone or in writing. Today, even rural Farm- or Ranch-to-MarketAASHTO replaced theAlthough the plans may say designedThese types of ratings are based on fieldAASHTO has included Load and Resistance FactorAs a result, TxDOT used theTexas initiated the concept of crown-widthTexas continued the crown-width,The allowable stressTruss countersIf a truss was designed H-15, H-20,Texas limited the distance between the concentratedThis is probably basedThis is probably the rationaleHowever, the 1953 THD Supplement No. http://www.tierambulanz-am-saarplatz.at/uploads/brother-mfc420cn-manual.xml

1 18 continued modifyingThe 30-ft limit may also have been inIn 1949, AASHTO changed this toThis changeThe AASHTO Bridge SpecificationsThis provisionIt is believed to be anFor this reason,For example, an H-15 design might rateEnter appropriate notationThe resulting stresses orDo not use temporary repairsThe Inventory Rating directly affectsNormally, if theMost of these bridges were designedUnfortunately,Design proceduresFor shorter, continuous bridges,However, the current AASHTOAs a result, this type of bridgeIn addition, continuous spans cannot beMost structures have a degree of capacityGenerate an LF rating in this case.These singleThe MBE defines 4 SHV trucks:By definition,Substructures do not need. All major structures and selected minor structures that carry vehicular traffic require a load rating.All major structures and selected minor structures that carry vehicular traffic require a load rating. For the full website experience, please update your browser to one of theIt could be because it is not supported, or that JavaScript is intentionally disabled. Some of the features on CT.gov will not function properly with out javascript enabled. Maintaining and improving upon the State's bridge inventory is necessary to accomplish this goal. A critical task for a bridge inventory to be in a good state of repair is the knowledge of each bridge's capacity to safely carry live loads in its current condition. A load rating package must provide this information in an accurate, organized, and standardized report. The information contained in this report is used for several purposes:Has the capability to import to Bridge Load Rating Form.The templates may or may not be compatible with previous or future versions; therefore, the Load Rating Section cannot guarantee the templates will work with versions other than those listed. http://www.drupalitalia.org/node/76638

LRFR is a statistically-based, more accurate and defensible load rating than the previous method, now referred to as the Tier-1 Load Rating Procedures. ODOT bridges will use the Oregon-specific live load factors and all other bridges will use the re-calibrated national live load factors. It has known security flaws and may not display all features of this and other websites. Learn how. The program is responsible for ensuring that all bridges are load rated to verify their safe load carrying capacity in accordance with the National Bridge Inspection Standards (NBIS). The Bridge Load Rating Unit performs load capacity evaluations of complex bridges, truss bridges, movable bridges, and all other structures within the state-owned inventory. The area also serves as the technical consultant to FHWA, MDOT Divisions, regions, and local agencies, and is responsible for assisting in FHWA NBIS Metric evaluations. The AASHTO Manual for Evaluation of Bridges (MBE) published in 2008 provides a choice of load rating methods. MBE Section 6 Part A incorporates provisions specific to the Load and Resistance Factor Rating (LRFR) method developed to provide uniform reliability in bridge load ratings, load postings, and permit decisions. Part B provides safety criteria and procedures for the Allowable Stress and Load Factor methods of evaluation. While most bridge ratings continue to be performed using the Load Factor Rating (LFR) method, several states are currently making their transition to the LRFR methodology following the provisions contained in the 2008 AASHTO MBE. Bridges designed using the LRFD method should be load rated using LRFR for reporting to the National Bridge Inventory. The purpose of this course is to concentrate on the fundamentals of load rating highway bridges using the latest AASHTO Manual for Bridge Evaluation. http://ambarevleri.com/images/bridge-cs4-manual.pdf

The course will begin with an overview of the AASHTO MBE, load rating methods, and introduce the load and resistance factor philosophy for new bridge designs and for load rating of existing bridges. The LFR and LRFR approaches are broken down into their basic components and a detailed explanation is provided on how and why each component was developed. LFR and LRFR live load models, load factors, distribution factors, load combinations, and rating provisions for steel and concrete bridges will be reviewed. Posting and permitting procedures specific to each methodology will be described. Examples with detailed step-by-step explanations will be used to illustrate the LFR and LRFR rating procedures. Fatigue evaluation methods for steel bridges and load rating of bridges by load testing are additional topics included in this course that follow the requirements of Sections 7 and 8 of the AASHTO MBE. Participants will also be instructed on the use of refined methods of analysis in load ratings and permitting, and their potential benefits. https://cashofferoregon.com/wp-content/plugins/formcraft/file-upload/server/content/files/16287363980683---cagiva-planet-125-manual-pdf.pdf

Seminar Benefits Understand the requirements for bridge evaluation contained in the AASHTO MBE Understand the fundamentals of the LFR and LRFR methodologies Understand the fundamentals of structural reliability and calibration of the LRFR Specifications Understand the new technologies introduced in the AASHTO MBE comparison of LFR and LRFR ratings Learn how to interpret and apply the MBE provisions to bridge load rating Learn through easy-to-follow rating examples with detailed explanations Get the latest information on load rating research and software Learn how to load rate bridges for legal loads and permit loads and superloads using the latest LRFR Learn how to evaluate bridges for fatigue cracking Learn how to load rate bridges by load testing to achieve enhanced capacity Learn how to utilize refined analysis methods to improve load ratings Obtain an understanding of how to plan and implement effective load rating and permitting policies and procedures using the latest MBE in your State Learning Outcomes Provide bridge engineers the fundamental knowledge necessary to apply the provisions of the 2008 AASHTO Manual for Bridge Evaluation for load rating highway bridges. Assessment of Learning Outcomes Achievement of the learning outcomes will be assessed through a series of case studies and problem-solving exercises. See discount deadline and rates below. Abstract This paper presents a comparison of three methods used to load rate the Powder Mill Bridge based on the load and resistance factor rating (LRFR) approach. This is a typical three-span continuous bridge with steel girders in composite action with the RC bridge deck. BANGKOKCABLE.COM/ckf_bccUpload/files/component-and-vendor-manuals.pdf

The three methods are as follows: (1) employing the conventional design office load rating technique using a simplified line girder analysis, (2) using strain measurements from a diagnostic load test to adjust the design office rating to account for in-situ bridge behavior, and (3) using a finite-element (FE) model of the bridge, which accounts for three-dimensional (3D) structural system behavior. Advantages and disadvantages of each method are related to speed, ease of use, reviewability, cost, accuracy, and type of use intended. Similarities and differences in utilizing these three methods are discussed. The advanced load rating methods are shown to produce higher ratings in comparison with the conventional approach. Download full-text PDF This is a typical three-span continuous bridge with steel girders in composite action with the RC bridge deck. Advantages and disadvan- tages of each method are related to speed, ease of use, reviewability, cost, accuracy, and type of use intended. Author keywords: Bridge load rating; Nondestructive testing methods; Finite-element modeling. Introduction According to the ASCE, the average highway bridge was 42 years old in 2013, approaching the 50-year design life typical of most bridges ( ASCE 2013 ). In 2008, AASHTO reported that truck miles traveled over bridges had nearly doubled over the previous 20 years and were expected to continue growing steadily ( AASHTO 2008 ). Freight volumes were also projected to double by 2025. In additio n, approximately 13 of the nation ’ s bridges were rated as struc- turally deficient, while approximately 12 were considered func- tionally obsolete ( AASHTO 2008 ). In the AASHTO publication Bridging the Gap, the researchers observe that “ While 50 years ago the nation faced an historic period of bridge construction, today it faces an historic period of bridge repair and reconstruct ion ” ( AASHTO 2008 ). {-Variable.fc_1_url-

The I-35 W Bridge ’ s tragic collapse in Minneapolis, Minnesota, on August 1, 2007 spurred renewed interest and urgency for ensur- ing the safety of the nation ’ s bridges. In 2008, the Federal Highway Administration (FHW A) initiated the Long Term Bridge Perfor- mance (LTBP) program to improve understanding of bridge perfor- mance and promote the safety and reliability of the nation ’ s bridges ( FHW A 2011 ). This gap in funding makes the e val- uation of bridge performance a significant issue. A white paper issued by the Structural Engineering Institute (SEI), in conjunction with ASCE and AASHT O, emphasized th e importance of obtain ing accurate loa d ratings and the critic al role of new techno logies sup- plementar y to visual insp ection ( ASCE 2009 ). Improvem ents in evalu ation may lead to more ef ficient alloc ation of limited resour ces. Bridges are required to be visually inspected every 2 years ( FHW A 2012 ). Each bridge component is assigned a numerical condition rating between 0 and 9, with a component rating 4 or lower classified as structurally deficient. Moore et al. ( 2001 ) inves- tigated the variability in visua l inspections by comparing evalua- tions performed on the same bridges by 49 different inspectors. The study found that on average, each element was assigned four to five different condition rating values, highlighting the difficulty in obtaining objective visual evaluations. In addition to inspections, bridge owners may specify load rat- ings to evaluate bridge performance ( AASHTO 2011 ). The process for load rating includes a more detailed inspection and a calcul ation of the live load capacity of a bridge. Results of the load rating in- spection are used for member capacity analyses to dete rmine the safe live load capacity of the bridge. When the capacity of a bridge is found to be less than is required, the bridge can be posted with limitations for the maximum truck load to restrict vehicles that can- not be safely carried. https://www.a2zmedical.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/16287366723d47---cagiva-raptor-1000-service-manual.pdf

The results of load ratings impact decisions regarding allocation of funds for bridge rehabilitati on and replace- ment. Thus, accurate load ratings are critical for effective bridge management. The conventional method for bridge load rating uses two- dimensional (2D), girder-by-girder analysis, and is the standard practice in bridge engineering. In this method, components of a bridge are isolated and analyzed for the maximum demands, not accounting for the in-situ three-dimensional (3D) system behavior of the bridge. Though the resulting load ratings are conservative, they do not accurately model the true behavior of the bridge. Ac- counting for factors such as deck continuity, diaphragms, and para- pet stiffness is more representative of the 3D system load transfer. 1 Professor, Dept. of Civil and Environmental Engineering, T ufts Univ., Medford, MA 02155 (corresponding author). Discussion period open until August 30, 2015; separate discussions must be submitted for individual papers. Copyright ASCE. For personal use only; all rights reserved. A finite- element (FE) model of a bridge, created based on experience and engineering judgment, can also be used to calculate a load ratin g. This paper will explore the use of these advanced load rating tech- niques in comparison with the conventional method. Substantial research has been conducted in the fields of load rating, nondestructive testing (NDT), and finite-element model cal- ibration. Bre ? na et al. ( 2013 ) evaluated a damaged bridge by non- destructive testing methods, using the data collected to identify alternate load distribution paths caused by girder damage. Schiebel et al. ( 2002 ) monitored the repair of three posted bridges and used diagnostic load testing to confirm the expected additional capacity after rehabilitation. This data was ultimately used in recommending the load posting be removed ( Schiebel et al. 2002 ). Chajes et al. BANGDIENTUNHK.COM/upload/files/compobus-s-operating-manual.pdf

( 1997 ) used NDT to investigate the unintended composite action of a posted bridge, concluding that the load rating could be in- creased based on the load test data. Y ost et al. ( 2005 ) used strain data collected from nondestructive load testing to calibrate a finite- element model. It was observed that load ratings calculated using the FE model were higher than those calculated using the conven- tional method ( Y ost et al. 2005 ). The conservatism of the AASHTO load and resistance factor design (LRFD) distribution factors has been previously documented ( Catbas et al. 2012; Y ousif and Hindi 2007; Barr et al. 2001; Y ost et al. 2005 ). Catbas et al. ( 2001 ) load rated a RC T-beam bridge for an HS-20 truck by load factor rating (LFR) using a variety of methods. The paper discussed the use of fleet health monitoring using a statisticall y representative sample of bridges to characterize an overall population. DeWolf ( 2009 ) used short-term field monitoring on deteriorating bridges to provide the Connecticut DOT with guidance on rehabilitation. The research showed significant cost savings and demonstrated the feasibility of DOTs effectively employing field monitoring techniques ( DeWolf 2009 ). Powder Mill Bridge The Powder Mill Bridge (PMB) is a three-span continuous composite concrete slab on steel girder bridge over the Ware River through V ernon Avenue in Barre, Massachusetts, sho wn in Fig. 1. Owned by the To wn of Barre, the PMB was designed by Fay, Spofford, and Thorndike (FST) in 2004 for a HS-25 loading using allowable stress design (ASD). The bridge is 47-m (154.2-ft) long, with a center span of 23.5 m (77.1 ft) and ends spans 11.75 m (38.6 ft) in length. The bridge is non- skewed and carries two lanes of traffic and a sidewalk. Sanayei et al. ( 2012 ) and Phelps ( 2010 ) provides additional information regard- ing the FE model. The PMB was instrumented as part of a National Science Foundation Partnerships for Innovation (PFI) project entitled, “ Whatever Happened to Long Term Bridge Design? ” All instru- mentation was installed during construction, and consists of 100 strain gauges, 36 steel temperature sensors, 30 embedded concrete temperature sensors, 16 uniaxial accelerometers, 16 biaxial tilt- meters, and two pressure plates ( Sanayei et al. 2012 ). Strain gauge measurements were used to load rate the PMB. During instrume n- tation, strain gauges were placed on each span as close as possible to maximum moment locations at the midspan and piers. In the negative moment zone, a nominal distance was kept between the strain gauges and the bearing pads to prevent reading of local stress concentrations. All sensors were connected to a data acquisition system located underneath the deck near the south abutment, shown in Fig. 2. Bridge Load Rating Load rating is used to quantify the live load capacity of a bridge. A rating of 1.0 or higher means the bridge can safely carry the vehicle it was rated for. Each structural component is rated individually, with the lowest individual component rating controlling the overall load rating of the bridge. There are two different levels of load rat- ing, as follows: (1) inventory, and (2) operating. The inventory rat- ing level represents the routine live load capacity that the bridge can support over an indefinite period of time. Copyright ASCE. For personal use only; all rights reserved. AASHTO ( 2011 ) outlines three methods for load rating, as fol- lows: (1) allowable stress rating (ASR), (2) load factor rating, and (3) load and resi stance factor rati ng. Federal High way Administrat ion policy requ ires bridges desi gned by ASD to be rated by either LFR or LRFR. This po licy also mandat es that all bridges designed after October 1, 2007, use LRFD specifications, part of the national trend in the direction of LRFR ( FHW A 2006 ). For this reason, LRFR was deemed appropriate for the research reported in this paper and was used for all three methods of load rating. The LRFR method is calibrated for the HL-93 live loading. Bridges rated for HL-93 use the governing condition of three load cases, as follows: (1) design truck with design lane load, (2) design tandem with design lane load, or (3) 90 of two design trucks with design lane load for the negative moment region. Load Case 1 con- trolled the PMB rating. When the HL-93 rating for a bridge falls below 1.0, the bridge is rated for a sui te of legal truck configura- tions, representing the maximum loads allowed on the bridge. AASHTO has three legal truck loadings, and states often have addi- tional legal loads that are more representative of vehicles in their regions. The HL-93 loading acts as an envelope for all AASHTO legal trucks and all legal truck configurations that fall within exclusion limits outlined by AASHTO design specifications ( AASHTO 2010 ). Thus, bridges with sufficient HL-93 ratings have adequate capacity for all AASHTO legal loads and all state legal loads within exclusion limits ( AASHTO 2011 ). The first load rating approach examined in this paper is the con- ventional design office load rating using a simplified line girder analysis. In practice, this is often automated using Virtis, a program developed by AASHTOW are. The second approach modifies the conventional rating method using NDT data, capturing the in-situ behavior of the bridge under loading. The third method uses a 3D FE model, carefully modeled by an experienced bridge engineer, to more accurately represent the true behavior of the bridge. The developers of Virtis recently included 3D finite-element analy- sis (FEA) in the bridge load rating feature of the product, highlight- ing the trend towards more advanced load rating methods ( AASHTO 2012 ). The basis for the difference in load rating methods is the live load distribution factor, which dictates the transverse distribution of the load to the bridge girders. Approximate live load distribution factors have been used in traditional bridge analysis and design as a way of enveloping maximum impacts on individual structural components. By conservatively distributing live loads to indi vidual girders, a simplified 2D line girder analysis can be performe d. The traditional method uses a conse rv ative approach for live load dis- tribution as outlined by AASHTO ( 2010 ). For the PMB moment load rating, the conventional approach applies 54 of the HL-93 loading to each of the two exterior girders and 63 to each of the four interior girders. These distribution factors do not account for system behavior. In reality, the girders share the load more than these factors predict. The FE model more closely models the actual distribution of the live loads, resulting in a load rating that is more representative of the actual structural system behavior. Conventional Load Rating Method The LRFR load rating equation for rating factor (RF) is given as ( AASHTO 2011 ) RF. DC is the DC load factor, equal to 1.25. The variable DW accounts for the wearing surface and utility dead loads; these have more uncertainty, resulting in the load factor. DW to be assigned a value of 1.5. If the wearing surface is field verified, ? DW is 1.25. The live load (LL) is multiplied by an impact factor (IM) of 1.33 to account for the dynamic load effect of the truck. The live load is further increased by. LL, equal to 1.75 for the inventory rating and 1.35 for the operating rating. The PMB is a three-span continuous bridge, requiring rating factors to be calculated in the positive and negative bending moment regions. The negative region controlled the rating. For this reason, only ratings for the negative region are presented. The wearing surface was distributed uni formly across all girders ( MassDOT 2007 ). The PMB carries a water utility pipe between Girders 4 and 5 that was conservatively assumed to be full. This load was distributed evenly between the adjacent girders. The depth of the haunch was conserva- tively neglected in section property calculations due to its variabil- ity ( MassDOT 2008 ). The concrete in the negative bending region was assumed to be cracked under governing loads, and so the capacity calculation included the stiffness of rebars in the negative region but not the concrete. The exterior girders were expected to rate higher than the interior girders due to the higher steel section modulus and smaller live load distribution factor. The rating factors bar chart for the conventional load rating method is shown in the “ Discussion of Rating Factors ” section. Conventional Load Rating Modified by Nondestructive Testing The second load rating was performed using diagnostic NDT data to improve the conventional rating. Diagnostic load tests can be performed to monitor a bridge ’ s response to known loading con- ditions. During a load test, the response of a bridge is monitored and compared with the analytical response. In most cases, the live load strains measured during the load test are smaller than expected due to increased live load distribution previously unaccounted for. Since the NDT rating is based on the structure ’ s response to loading, it can be considered a more accurate load rat- ing reflecting the actual capacity of the bridge at the time of testing. A diagnostic load test was conducted at the PMB on September 25, 2011, the results of which were used for the load rating pre- sented in this paper. No deterioration was observed on the bridge prior to the load test. The National Cooperative Highway Research Program (NCHRP) provides direction for load rating by nonde- structive testing, and was used as the basis for these calculations ( NCHRP 1998 ). A triaxle dump truck was loaded to 353.59 kN (79.48 kip) for the load test. The first, second, and third axles weighed 84.79 kN (19.06 kip), 134.79 kN (30.30 kip), and 134.01 kN (30.12 kip), respectively. Ideally, a legal load vehicle is used for the load test; however, the NCHRP acknowledges that these are seldom available ( NCHRP 1998 ). Copyright ASCE. For personal use only; all rights reserved. Due to the location of the sidewalk, Girder 6 was not able to be stressed enough to validate an NDT rating. Eq. ( 2 ) was used to calculate the load rating based on NDT data ( AASHTO 2011 ) RF T. When K is greater than 1.0, the NDT rating is higher than the conventional rating. When K is less than 1.0, the NDT ratin g shows less capacity than the conventional calculation, and is scaled down. The adjustment factor K is used to describe the benefit derived from the load test. The K a term considers both theoretical and measured strains, while K b considers only theoretical results. The calculation of the theoretical strain also requires the calcu- lation of distribution factors for the load test truck on each girder. The purpose is to determine the anticipated strain based on the actual stress caused by the test truck on each girder. The NCHRP recommends calculating distribution factors based on the lever rule ( NCHRP 1998 ). The lever rule calculates the static summation of moments about one point in order to determine the reaction at a second point ( AASHTO 2010 ). This method simplifies the load distribution by treating the deck as simply supported in the trans- verse direction, allowing only girders directly adjacent to the load to participate in the load sharing. The lever rule predicted a distri- bution factor of 0.58 for the interior girders, which were fully stressed. The AASHTO distribution factor for an interior girder with one lane loaded, however, was 0.47.