ENCE466 Design and Analysis of Straight Highway Bridges Tutorial (for Steel Bridges) C. C. Fu, Ph.D., P.E. The BEST Center Department of Civil & Environ. Engineering University of Maryland 2010

Figure 1: Typical Bridge Cross Section DASH Input for Example 2 Figure 1: Typical Bridge Cross Section http://www.cee.umd.edu/best/ExSteeld1.dat

Bridge and Roadway Alignment

Bridge Superstructure Design

Bridge Substructure Design

Design Guidelines (1)

Design Guidelines (2)

DASH Input for Example 2 Span interval can be any numbers from 4-20 4 modes: Steel Composite & Noncomposite, RC & PC 8 modes for steel

DASH Input for Example 2 Position will affect the Effective Width and Distribution Factor Haunch will affect the section properties and weight % of composite will affect the moment distribution Detailed factor applied to steel section only

DASH Input for Example 2 Figure 2: Framing Plan

Distance between centerlines of bearings DASH Input for Example 2 Distance between centerlines of bearings

Spacing is required for Distribution Factor and DL calculation DASH Input for Example 2 Spacing is required for Distribution Factor and DL calculation

DASH Input for Example 2 Figure 3: Elevation of Interior Girder

2 unique PG sections are defined DASH Input for Example 2 2 unique PG sections are defined

DASH Input for Example 2 Members are defined from left to right in an ascending order These 3 entries are for non-prismatic members These 3 entries are for hybrid members

DASH Input for Example 2 HL-93 or HS loading from 1 to 99 If =2 proportional to the HS loading For fatigue use

DASH Input for Example 2 If not a staging case, slab loads have to be defined span by span or total span length. For a staging case, slab distances can be arbitrary. Pouring no. & Day are used for staging

Not for hybrid sections DASH Input for Example 2 For the proper calculation of moment capacity, distance has to be equally divided by the lateral bracing spacing Not for hybrid sections

MERLIN-DASH Execution Utility

Case Study: Bulb-Tee (BT-72), Single Span, Composite Deck, based on Standard Specifications Bridge Cross Section (Ref. PCI Bridge Design Manual Example 9-3)

Structural Details (03012) Position will affect the Effective Width and Distribution Factor Haunch will affect the section properties and weight These two entries are used for steel girder only

Span Lengths (03062) For single span, only input for Span Length (2) and Overhangs (1&3)

Beam Spacing (03042) Spacing is required for Distribution Factor and DL calculation

AASHTO-PCI-BT-72 Bulb-Tee Internally Stored Girder Sections in Win-DASH/P: AASHTO I – VI Bulb Tee BT-54, 63, & 72

PC Section (04012) ID 0 is for internally stored AASHTO Girder. 72 is for BT-72

Composite Section (calculated by Win-DASH/P)

Strand Pattern (Ref. PCI Bridge Design Manual)

Longitudinal Strand Profile (Ref. PCI Bridge Design Manual)

Member and Tendon Geometry (05032) Lines 1-4 are for straight tendons input by rows. Line 5 is for draped tendons input by groups where distance refers to the C.G. of the group

Arbitrary Uniform and Concentrated Loads (11012) SDL for wearing surface

Auto Generation of Dead and Superimposed Dead Loads (02012) Slab thickness for section property calculation and slab + integral wearing surface for DL calculation

Alternate Input of Slab Loads (10012) Slab thickness for section property calculation and intensity based on slab + integral wearing surface for DL

Slab Information (12034)

Precast Beam Information (12036) fc’ at 28 days is for service condition. fc’ at release is for initial condition

Prestressing Steel Properties (04032) fsi=0.75fs’ is used in this example If leaving blanks, losses will be calculated by the program based on the AASHTO