Publications

Export 16 results:
Sort by: Author [ Title  (Asc)] Type Year
A B C D E F [G] H I J K L M N O P Q R S T U V W X Y Z   [Show ALL]
A
Viana, L. A., Nunes A. Antão, Vicente M. da Silva, and N. M. C. Guerra The application of limit analysis to the study of the basal failure of deep excavations in clay considering the spatial distribution of soil strength. Proceedings of the 17 European Conference on Soil Mechanics and Geotechnical Engineering. Reykjavik, Islândia, 2019.
Deusdado, N., Nunes A. Antão, Vicente M. da Silva, and N. M. C. Guerra Application of the Upper and Lower-Bound Theorems to Three-Dimensional Stability of Soil Slope. 3 th International Conferen e on Transportation Geotechnics. Guimarães., 2016.
B
Franco, F., Nunes A. Antão, Vicente M. da Silva, and N. M. C. Guerra Bearing capacity of shallow impervious footing in soil under sub-vertical seepage. Pro eedings of the 18 th International Conference on Soil Mechanics and Geotechnical Engineering. Seoul, Coreia, 2017.
D
Antão, A. N., M. Vicente da Silva, and N. M. C. Guerra. "Determination of depth factors for the bearing capacity of shallow foundations in sand." Soils and Rocks. 33 (2010): 47-52. Abstract
n/a
F
Leal, R., Nunes A. Antão, and N. M. C. Guerra Flexible retaining structures supported by anchor beams: the problem of tie-rod length. Proceedings of the 16th European Conference on Soil Mechanics and Geotechnical Engineering. Edimburgo, Escócia: 3, 2015.
I
Antão, Armando N., Nuno Costa M. da Guerra, Manuel Matos Fernandes, and António Cardoso. "Influence of tension cut-off on the stability of anchored concrete soldier-pile walls in clay." Canadian Geotechnical Journal. 45 (2008): 1036-1044. AbstractWebsite

A previous paper studied the stability of soldier-pile walls in clay under vertical loading using upper bound analyses. A classical Tresca yield criterion was assumed in that analysis. This paper extends that study by considering a tension truncated Tresca yield criterion in an upper bound numerical analysis of the problem. It shows that assuming zero tension soil strength has a significant influence on the values of the minimum soldier-pile resistance required to ensure stability.

Josefino, Santos C. J., Costa N. M. da Guerra, and Nunes A. Antão. "Influence of the Embedded Length on the Overall Stability of Single Anchored Retaining Walls." Soils & Rocks. 40.2 (2017): 133-145.
O
Gonçalves, Rodrigo, David Henriques, Armando Antão, and Manuel Ritto-Corrêa. "On non-uniform plastic torsion of steel I-section cantilevers." Thin-Walled Structures. 187 (2023): 110731. AbstractWebsite

This paper aims at contributing towards a better understanding of the non-uniform elastoplastic torsion mechanism of I-section beams. The particular case of cantilevers subjected to an end torque is analysed, which constitutes a simple yet interesting problem, since the maximum torque is very close to the so-called Merchant upper bound (MUB), with added independent maximum bishear and Saint-Venant torques. Consequently, it turns out that the maximum torque can be significantly higher than that for uniform plastic torsion. Besides the MUB, several solutions are presented and compared, namely (i) a stress resultant-based solution stemming from the warping beam theory differential equilibrium equation and (ii) solutions obtained with several beam finite elements that allow for a coarse/refined description of warping. It is found that all models are in very close agreement in terms of maximum torque (including the MUB) and stress resultants. However, the beam finite elements that allow for bishear, even with a simplified warping function, are further capable of reproducing quite accurately the stress field, as a comparison with a 3D solid finite element solution shows. Although the paper is primarily concerned with the small displacement case, the influence of considering finite rotations is also addressed.

Guerra, N. M. C., Santos C. Josefino, and Nunes A. Antão Overall stability of anchored retaining structures: revisiting Broms' method. Proceedings of the Edinburgh and Pune Workshops of TC207 of ISSMGE. Edimburgo, Escócia, 2016.
P
Antão, Armando N., T. Santana, M. Vicente da Silva, and N. M. C. Guerra. "Passive earth-pressure coefficients by upper-bound numerical limit analysis." Canadian Geotechnical Journal. 48 (2011): 767-780. Abstract

A three-dimensional (3D) numerical implementation of the limit analysis upper-bound theorem is used to determine passive horizontal earth-pressure coefficients. An extension technique allowing determination of the 3D passive earth pressures for any width-to-height ratios greater than 7 is presented. The horizontal passive earth-pressure coefficients are presented and compared with solutions published previously. Results of the ratio between the 3D and two-dimensional horizontal passive earth-pressure coefficients are shown and found to be almost independent of the soil-to-wall friction ratio. A simple equation is proposed for calculating this passive earth-pressure ratio.

Simões, J. T., L. C. Neves, Nunes A. Antão, and Costa N. M. da Guerra. "Pro- babilisti analysis of bearing apa ity of shallow foundations using three-dimensional limit analyses." International Journal of Computational Methods. 11.2 (2014).
R
Simões, J. T., L. C. Neves, Nunes A. Antão, and Costa N. M. da Guerra. "Reliability assessment of shallow foundations on undrained soils considering soil spatial variability." Computers and Geotechnics. 119 (2020).
T
Antão, Nunes A., T. Santana, Vicente M. da Silva, and Costa N. M. da Guerra. "Three-dimensional active earth pressure coefficients by upper bound numerical limit analysis." Computers and Geotechnics. 79 (2016): 96-104.
Santana, T., Vicente M. da Silva, Nunes A. Antão, and N. M. C. Guerra Two dimensional upper and lower-bound numerical analysis of the basal stability of deep excavations in clay. Pro eedings of the 9 th European Conference on Numerical Methods in Geotechnical Engineering (NUMGE 2018). Porto, 2018.
U
Antão, Nunes A., N. M. C. Guerra, Vicente M. da Silva, and T. Santana Upper and lower bounds for the bearing apacity of foundations on soft soils with reinforcement columns. Proceedings of the 17 th European Conference on Soil Mechanics and Geotechnical Engineering. Reykjavik, Islândia, 2019.
Santana, T., A. Antão, N. Guerra, and M. Vicente da Silva. "Upper bounds for the three-dimensional seismic active earth pressure coefficients." Géotechnique Letters. 13 (2023): 65-74. AbstractWebsite

A numerical implementation of the upper-bound theorem of limit analysis is applied to determine two-dimensional (2D) and three-dimensional (3D) active horizontal earth pressure coefficients considering seismic actions through a horizontal seismic coefficient. Results are obtained for vertical wall, horizontal soil, different friction angles of the soil, soil-to-wall friction ratios, horizontal seismic coefficients and wall width-to-height ratios. The few cases for which 3D active earth pressure coefficients are available in the literature using upper-bound methods were used for comparison with the corresponding earth pressure coefficients obtained in this study. This showed a general improvement of these results, which allows expecting a good accuracy for the set of cases studied. The ratios between the 3D and 2D horizontal active earth pressure coefficients are found to be practically independent of the soil-to-wall friction ratio. An equation is proposed for calculating these ratios. This equation can be easily used in the design of geotechnical structures requiring the determination of 3D active earth pressure coefficients.