Determination of entrance loss coefficients for pre-cast reinforced Concrete Box Culverts, December 2012

There is an increased interest in constructing Pre-Cast (PC) Twin and Triple Reinforced Concrete Box (RCB) culverts in Iowa due to the efficiency associated with their production in controlled environment and decrease of the construction time at the culvert sites. The design of the multi-barrel PC culverts is, however, based on guidelines for single-barrel cast-inplace (CIP) culverts despite that the PC and CIP culverts have different geometry. There is scarce information for multiplebarrel RCB culverts in general and even fewer on culverts with straight wingwalls as those designed by Iowa DOT. Overall, the transition from CIP to PC culverts requires additional information for improving the design specifications currently in use. Motivated by the need to fill these gaps, an experimental study was undertaken by IIHR-Hydroscience & Engineering. The goals of the study are to document flow performance curves and head losses at the culvert entrance for a various culvert geometry, flow conditions, and settings. The tests included single-, double- and triple-barrel PC and CIP culverts with two span-to-rise ratios set on mild and steep slopes. The tests also included optimization of the culvert geometry entrance by considering various configurations for the top bevel. The overall conclusion of the study is that by and large the current Iowa DOT design specifications for CIP culverts can be used for multi-barrel PC culvert design. For unsubmerged flow conditions the difference in the hydraulic performance curves and headloss coefficients for PC and CIP culverts are within the experimental uncertainty. Larger differences (specified by the study) are found for submerged conditions when the flow is increasingly constricted at the entrance in the culvert. The observed differentiation is less important for multi-barrel culverts as the influence of the wingwalls decreases with the increase of the number of barrels.

Pilot Knob State Park, Merrick State Park, Eagle Lake State Park, Rice Lake State Park and Crystal, East and West Twin, and Duck Lakes,1925.

Provides information on Pilot Knob State Park, Merrick State Park, Eagle Lake State Park, Rice Lake State Park and Crystal, East and West Twin, and Duck Lakes including history, maps, location, terrain, photos, vegetation and wildlife.

Computer Analysis of Twin Box Culverts, 1959

The paper presents a method of analyzing Rigid Frames by use of the Conjugate Beam Theory. The development of the method along with an example is given. This method has been used to write a computer program for the analysis of twin box culverts. The culverts may be analyzed under any fill height and any of the standard truck loadings. The wall and slab thickness are increased by the computer program as necessary. The final result is steel requirements both for moment and shear, and the slab and wall thickness.