Tied-Back Top-Down Wall to Support I-295 Ramp

Woodrow Wilson Replacement Bridge Project included widening the Washington Beltway (I-95/I-495) Outer Loop from three lanes to six-lanes. This required supporting two existing ramps that connect I-295 and MD 210 as well as the existing Mechanically Stabilized Earth (MSE) wall that supports the ramps. The MSE is about 17-ft tall, about 570-ft long, and at the top of a slope. A tied-back soldier pile and lagging wall with cast-in-place facing was selected to support the MSE and the ramps. The new wall will be about 1,376-ft long and will be as high as 37-ft. The closest approach of the wall to the existing MSE is about 3-ft. Laboratory testing was supplemented with Dilatometer Test (DMT) and Cone Penetration Test (CPT) soundings. PYWall and PLAXIS were used to estimate wall deflections and bending moments in the soldier piles. This paper reviews the analysis techniques, describes the design and the construction methods, and the instrumentation used to monitor the wall and MSE movements. The results of the computer simulations were compared to the inclinometer results. As work progressed simulations were updated by modifying the soil parameters to obtain calculated results that are more nearly consistent with the instrumentation readings

Response of Wheat Genotypes to Different Levels of Nitrogen

A field experiment was conducted using six genotypes of wheat (Triticum aestivum L.) for response to different levels of nitrogen (N) use. The experiment was laid out in split plot design with four levels (0, 50, 100 and 150 kg N ha-1) as main plots and six wheat genotypes (BL 3623, BL 3629, BL 3872, NL 1008, NL 1055 and Vijay, a check variety) as sub-plots. Grain yield and other yield components increased linearly in response to N concentrations in both seasons. Only two parameters: days to heading (DOH) and days to maturity (DTM) varied significantly (p ≤ 0.05) among wheat genotypes in both the years. None of the parameters showed interaction effects in both seasons. Vijay showed highest grain yield of 3.12 t ha-1 in 2013 with the application of 100 kg N ha-1, and 3.23 t ha-1 in 2014 with 150 kg N ha-1. Spike length, productive tillers m-2, number of spikes m-2 and test weight were greater with higher N rates. The straw yield of wheat fertilized with 150 kg N ha-1 was the highest in Vijay (4.35 t ha-1) and BL 3872 (4.33 t ha-1), respectively. Vijay with 100 kg N ha-1 produced the highest number of productive tillers m-2 (276.33) in 2013 and 296.00 with the application of 150 kg N ha-1 in 2014