1. K.B. Benedict, J.E. Lee, N. Kumar, P.S. Badal, M. Barbato, M.K. Dubey, and A.C. Aiken, (2024). “Wildland Urban Interface (WUI) Emissions: Laboratory Measurement of Aerosol and Trace Gas from Combustion of Manufactured Building Materials.” ACS ES&T Air, American Chemical Society, https://doi.org/10.1021/acsestair.4c00217.

2. E.L. Rengifo-López, N. Kumar, F. Matta, and M. Barbato, (2024). “Homogeneity and Isotropy of Compressed and Stabilized Earth Block Material: Mechanical characterization and statistical analysis.” Journal of Materials in Civil Engineering, ASCE, https://doi.org/10.1061/JMCEE7.MTENG-17488.

3. N. Kumar, M. Barbato, E.L. Rengifo-López, and F. Matta, (2023). “Finite Element Detailed Micromodeling of Unreinforced Earth Block Masonry System.” Journal of Structural Engineering, ASCE, 149(7). https://doi.org/10.1061/JSENDH.STENG-12093

4. S. Subedi, G. Arce, M. Hassan, M. Barbato, M.T. Gutierrez-Wing, and N. Kumar, (2023) “Louisiana’s Sugarcane Bagasse Ash Utilization for Partial Cement Replacement in Concrete for Transportation Infrastructure Applications.” International Journal of Pavement Research and Technology, https://doi.org/10.1007/s42947-022-00258-8

5. N. Kumar, M. Barbato, E.L. Rengifo-López, and F. Matta, (2022). “Capabilities and Limitations of Existing Finite Element Simplified Micro-Modeling Techniques for Unreinforced Masonry: General Considerations and Case Studies.” Research on Engineering Structures & Materials, 8(3): 463-490. http://dx.doi.org/10.17515/resm2022.408st0226 (2022 Best Paper Award)

6. N. Kumar, and M. Barbato, (2022). “Effect of Sugarcane Bagasse Fiber on the Properties of Compressed and Stabilized Earth Blocks.” Construction and Building Materials, Elsevier, 315: 125552. https://doi.org/10.1016/j.conbuildmat.2021.125552

7. N. Kumar, and M. Barbato, (2019). “Interface Element Constitutive Model for Finite Element Modeling of Masonry.” Journal of Engineering Mechanics, ASCE, 145(5): 04019022. https://doi.org/10.1061/(ASCE)EM.1943-7889.0001592

8. N. Kumar, M. Barbato, and R. Holton, (2018). “Feasibility Study of Affordable Earth Masonry Housing in the U.S. Gulf Coast Region.” Journal of Architectural Engineering, ASCE, 24(2): 04018009. https://doi.org/10.1061/(ASCE)AE.1943-5568.0000311

9. N. Kumar, H. Lambadi, M. Pandey, and A. Rajagopal, (2016). “Homogenization of Periodic Masonry Using Self-Consistent Scheme and Finite Element Method.” International Journal for Computational Methods in Engineering Science and Mechanics, Taylor & Francis, 17 (1), 7-21. https://doi.org/10.1080/15502287.2015.1137091

10. N. Kumar, and D.R. Sahoo, (2016). “Optimization of Lip Length and Aspect ratio of Thin-channel Sections under Minor Axes Bending.” Thin-walled Structures, Elsevier, 100, 158-169. https://doi.org/10.1016/j.tws.2015.12.015

11. D.R. Sahoo, and N. Kumar, (2015). “Monotonic Behavior of Large-scale SFRC Beams Without Stirrups.” Engineering Structures, Elsevier, 92, 46-54. https://doi.org/10.1016/j.engstruct.2015.03.014

12. P.C.A. Kumar, D.R. Sahoo, and N. Kumar, (2015). “Limiting Values of Slenderness ratio for Circular Braces of Concentrically Braced Frames.” Journal of Constructional Steel Research, Elsevier, 115, 223-235. https://doi.org/10.1016/j.jcsr.2015.08.026

13. N. Kumar, M. Pandey, and A. Rajagopal, (2014). “A Rate Independent Cohesive Zone Model for Modeling Failure in Quasi-Brittle Materials.” Mechanics of Advanced Materials and Structures, Taylor & Francis, 22(8), 681-696. https://doi.org/10.1080/15376494.2013.855852

14. N. Kumar, M. Pandey, and A. Rajagopal, (2014). “Plasticity Based Approach for Failure Modelling of Unreinforced Masonry.” Engineering Structures, Elsevier, 80, 40-52. https://doi.org/10.1016/j.engstruct.2014.08.021

1. N. Kumar, M. Barbato, E.L. Rengifo-López, and F. Matta, (2023). “Accurate simulation of mechanical behavior of unreinforced earth block masonry via finite element detailed micro-modeling.” Proceedings for the fourteenth North American Masonry Conference (14th NAMC), The Masonry Society (TMS), 141-153, 14th NAMC, June 9 - 14, Omaha, Nebraska, USA. ISBN: 978-1-7138-7786-8

2. S. Subedi, G. Arce, M. Hassan, N. Kumar, M. Barbato, and M.T. Gutierrez-Wing, (2020) “Influence of Production Methodology on the Pozzolanic Activity of Sugarcane Bagasse Ash.” Proceedings for the 2019 Transportation Consortium of South-Central States Conferences, MATEC Web of Conferences, 271, Tran-SET Annual Conference, Jan 12 - 16, Washington, D.C., USA. https://doi.org/10.1051/matecconf/201927107003

3. E.L. Rengifo-López, N. Kumar, F. Matta, and M. Barbato, (2019). “Experimental and Numerical Study of Uniaxial Compression Behavior of Compressed and Stabilized Earth Blocks.” Proceedings for the thirteenth North American Masonry Conference (13th NAMC), The Masonry Society (TMS), 925-936, 13th NAMC, June 16 - 19, Salt Lake, Utah, USA. ISBN: 978-1-5108-9019-0.

4. E.L. Rengifo-López, N. Kumar, F. Matta, and M. Barbato, (2018). “Can Compressed and Stabilized Earth Block Materials be Regarded as Homogeneous and Isotropic?” Proceedings for the tenth International Masonry Conference (10th IMC), International Masonry Society (IMS), 10th IMC, July 9 - 11, Milan, Italy.

5. R. Holton, M. Barbato, and N. Kumar, (2018). “Resilient and Affordable Housing for the US Gulf Coast: Earthen building materials re-appropriated for use in hot wet climates.” Proceedings for ARCC-EAAE 2018 International Conference, ARCC Conference Repository, ARCC-EAAE 2018 International Conference, May 16 - 19, Philadelphia USA. https://doi.org/10.17831/rep:arcc%25y559

6. P.C.A. Kumar, D.R. Sahoo, and N. Kumar, (2015). “Limiting Slenderness ratio for Hollow Square Braces in Special Concentrically Braced Frames.” Proceedings for the tenth Pacific Conference on Earthquake Engineering (PCEE) Building an Earthquake-Resilient Pacific, PCEE 2015, Nov 6 - 8, Sydney, Australia.

7. P.C.A. Kumar, N. Kumar, and D.R. Sahoo, (2014). “Evaluation of Limits of Slenderness ratio of Braces used in Special Concentrically Braced Frames.” Proceedings for the 7th European conference on steel and composite structures, EUROSTEEL 2014, Sept 10 - 12, Naples, Italy.

1. N. Kumar, and M. Barbato, (2022). “Effect of High Temperatures on Flexure Strength of Compressed and Stabilized Earth Blocks.” Earth USA 2022 Proceedings, Adobe in Action, Earth USA 2022, Sept 23 - 25, Santa Fe, New Mexico, USA.

2. N. Kumar, M. Barbato, E.L. Rengifo-López, and F. Matta, (2022). “Finite Element Micro-modeling of Earth Block Masonry Systems.” Earth USA 2022 Proceedings, Adobe in Action, Earth USA 2022, Sept 23 - 25, Santa Fe, New Mexico, USA.

3. N. Kumar, and Barbato, (2019). “Properties of Compressed and Stabilized Earth Blocks Produced with Recycled Soil Mixes.” Earth USA 2019 Proceedings, Adobe in Action, 254-261, Earth USA 2019, October 25 - 27, Santa Fe, New Mexico, USA.

4. E.L. Rengifo-López, N. Kumar, F. Matta, and M. Barbato, (2019). “Experimental characterization and numerical simulation of compressive behavior of compressed and stabilized earth block specimens.” Earth USA 2019 Proceedings, Adobe in Action, 314-321, Earth USA 2019, October 25 - 27, Santa Fe, New Mexico, USA.

5. E.L. Rengifo-López, N. Kumar, F. Matta, and M. Barbato, (2017). “Variability of Compression Strength and Stiffness in Compressed Stabilized Earth Blocks.” Earth USA 2017 Proceedings, Adobe in Action, Earth USA 2017, Sept 29 - Oct 1, Santa Fe, New Mexico, USA.

6. N. Kumar, and M. Barbato, (2017). “Compressed and Stabilized Earth Blocks in Louisiana.” Earth USA 2017 Proceedings, Adobe in Action, Earth USA 2017, Sept 29 - Oct 1, Santa Fe, New Mexico, USA.

7. M.S. Pandikkadavath, N. Kumar, and D.R. Sahoo, (2014). “Evaluation of Energy Parameters of Short Length Buckling-restrained Braces.” Proceedings for 15th Symposium on Earthquake Engineering (15SEE), 15SEE, Dec 11 - 13, Indian Institute of Technology Roorkee, Uttarakhand, India.

8. N. Kumar, P.C.A. Kumar, and D.R. Sahoo, (2014). “Optimum Range of Slenderness ratio for Braces in Special Concentric Braced Frames.” Proceedings for the 5th Asia Conference on Earthquake Engineering (ACEE), ACEE 2014, Oct 16 - 18, Taipei, Taiwan.

9. N. Kumar, and A. Rajagopal, (2012). “Masonry Failure Analysis using Composite Interface Model.” Proceedings for 4th International Congress on Computational Mechanics and Simulation (ICCMS), ICCMS 2012, Dec 9 - 12, Hyderabad, Telangana, India.

1. N. Kumar, and M. Barbato, (2023). “Mechanical Strength of Compressed and Stabilized Earth Blocks Subject to Elevated Temperatures.” Proceedings (abstract), Wildfire Resilient Structures (WiReS) Conference and Tradeshow, Feb 7 - 10, San Diego, California, USA.

2. N. Kumar, P.S. Badal, and M. Barbato, (2023). “Comparison of wildfire emissions from wooden and earthen buildings in the WUI.” Proceedings (abstract), Wildfire Resilient Structures (WiReS) Conference and Tradeshow, Feb 7 - 10, San Diego, California, USA.

3. N. Kumar, and M. Barbato, (2019). “An Efficient and Robust Interface Element Constitutive Model for Finite-Element Modeling of Masonry.” Proceedings (abstract and poster), International Mechanical Engineering Congress & Exposition 2019, Nov 11 - 14, Salt Lake City, Utah, USA.

4. N. Kumar, and M. Barbato, (2018). “Towards an Efficient and Robust Simplified Micro-model for analyzing Masonry Shear Wall.” Proceedings (abstract and poster), Engineering Mechanics Institute Conference 2018, May 29 - June 1, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA.

5. N. Kumar, and M. Barbato, (2018). “Compressed and Stabilized Earth Blocks reinforced with Sugarcane Bagasse Fiber” Proceedings (abstract and poster), 7th Annual CEE Graduate Student Research Conference 2018, April 6, Louisiana State University, Baton Rouge, Louisiana, USA.

6. N. Kumar, and M. Barbato, (2016). “Feasibility Study of Low-Cost Hurricane-Resistant CSEB Structural Systems.” Proceedings (abstract and poster), 5th Annual CEE Graduate Student Research Conference 2016, April 6, Louisiana State University, Baton Rouge, Louisiana, USA.

7. N. Kumar, and M. Barbato, (2015). “A Numerical Study of Compressed and Stabilized Earth Blocks.” Proceedings (abstract and poster), 4th Annual CEE Graduate Student Research Conference 2015, April 3, Louisiana State University, Baton Rouge, Louisiana, USA.

8. A. Rajagopal, N. Kumar, and M. Pandey, (2013). “Cohesive Zone Modelling for the Cracking, Slipping and Crushing in Quasi Brittle Materials.” Proceedings (abstract), SIMULIA Regional User Meeting, Oct 22, Bengaluru, India.

1. N. Kumar, “The Camp Fire & Paradise, CA, Climate Change, Wildland Urban Interface, & Building Innovations.” Invited Zoom Seminar, The Science of Disaster II:  Building Resiliency thru Architecture & Engineering, Nov 13, 2021, Girl Scouts of the USA.

2. N. Kumar, “Lecture on Tributary and Influence Areas.” Invited Zoom Lecture, Structural Loads: Calculation & Modeling, Jan 13, 2022, Department of Civil and Environmental Engineering, University of California, Davis, California, USA. Instructor: Prof. M. Barbato

3. N. Kumar, “Principles of Capacity-Based Earthquake-Resistant Design", Jan 27 2025, Rajgir International Convention Center, Nalanda, Bihar, India.

Kumar, N. (2022) “Mechanical and Structural Behavior of Compressed and Stabilized Earth Block Masonry Systems.” PhD Dissertation, Department of Civil and Environmental Engineering, University of California Davis, Advisor: Prof. Barbato, M., Davis, California (USA). https://www.proquest.com/docview/2796379135

Earthen masonry has been used since prehistoric times to build structures primarily made from soil. In the modern era of concrete and steel, earthen structures have seen a significantly reduced usage, because of their relatively low strength and lack of standardization. However, they are once again getting attention because of their low cost, low carbon footprint, energy efficiency, use of indigenous materials, and inherent simplicity. In particular, compressed and stabilized earth block (CSEB) construction is appealing as a viable response to the lack of affordable housing in the US and worldwide, as over two billion new houses will be needed in the next 80 years.

Currently, only few building codes in the US allow the use of CSEB construction through a prescriptive approach adapted from ordinary masonry. As a result, earthen buildings represent only a small fraction of the building inventory in the US, even in places where this type of construction is historically established and culturally appreciated. The CSEB construction is even rarer in locations with humid and rainy climates such as the US Gulf Coast, because of the poor resistance to degradation experienced by traditional earthen construction and its widespread perception as a substandard structural choice under extreme wind loads. Therefore, the present research aims to engineer modern earthen construction by: (1) demonstrating the feasibility of CSEB masonry housing in the US Gulf Coast region; (2) enhancing the properties of CSEBs using sugarcane bagasse fibers, an agricultural by-product; (3) developing a computationally efficient and robust interface element’s constitutive model for simulating the mechanical behavior of masonry; (4) investigating the capabilities and limitations of finite element (FE) simplified micro-modeling techniques that are frequently used for simulating the behavior of ordinary masonry; and (5) developing an FE detailed micro-model specifically tailored for earth block masonry systems. The results of this research represent an advancement in the engineering knowledge necessary for (1) promoting CSEB construction that can endure humid climate and hurricane wind, and (2) understanding the structural behavior of CSEB masonry, which is ultimately required for developing material-specific design standards of CSEB masonry systems.