Evaluasi Variabilitas Kinerja Struktur Perkerasan Jalan Berbasis Pengujian Seismik

Evaluasi perkerasan jalan diperlukan untuk memeriksa kerusakan awal yang terjadi pada perkerasan. Penilaian perkerasan dilakukan untuk memprediksi kualitas material perkerasan secara fungsional dan struktural. Penelitian ini bertujuan untuk menilai dan mengevaluasi perkerasan jalan secara struktural menggunakan pengukuran seismik Spectral Analysis of Surface Waves (SASW). Metode SASW menguji sifat material perkerasan sebagai teknik evaluasi struktural. Metode SASW merupakan metode seismik non-destruktif yang menghasilkan, mengukur, dan memproses gelombang Rayleigh yang terdispersi. Selanjutnya, proses inversi dengan teknik optimasi digunakan untuk menganalisis data dispersi gelombang Rayleigh guna menghasilkan profil kekakuan setempat, dalam parameter kecepatan gelombang geser dan modulus elastisitas. Parameter kekakuan dari metode ini yang dihasilkan pada tingkat regangan mikroskopis yaitu kurang dari 0,001%, di mana pada tingkat ini, bahan tanah berperilaku elastis linier. Hasil dari uji SASW selanjutnya dibandingkan dengan uji Marshall dan nilai uji Dynamic Cone Penetrometer (DCP). Pengamatan visual juga dilakukan untuk menentukan penilaian fungsional untuk mengukur seberapa besar kerusakan permukaan jalan. Hasil penelitian menunjukkan bahwa metode SASW dapat secara efektif mengukur kecepatan gelombang geser dan variabilitas modulus elastisitas pada setiap lapisan perkerasan. Studi ini merekomendasikan pengujian seismik untuk memeriksa variabilitas kinerja struktural perkerasan jalan terpasang

Pengaruh Penggunaan Abu Sekam Padi sebagai Bahan Pengisi pada Campuran Hot Rolled Asphalt terhadap Sifat Uji Marshall

Rice Husk Ash (RHA) has fairly high content of SiO2 and easily obtainable. It is inexpensive since it is the residual waste of the tile or brick combustion process that is not utilized properly. RHA has the potential to be used as filler in Hot Rolled Asphalt (HRA) since it has high flexibility mixture design. The influential characteristic of RHA is that it has fine aggregate fraction. This study aims to discover the physical properties of RHA, the characteristic of the Marshall test properties, the optimum bitumen content, and the economical comparison between the RHA-mixed HRA and the conventional one using stone dust filler. The results of this study indicate that the use of the RHA is able to increase the optimum bitumen content. In terms of economical comparison, the use of RHA as filler material is much more economical than using stone dust as filler

WSASW Application for Soil Dynamic Properties in Soft Soil Investigation at Kelang, Malaysia

In seismic wave measurements, soil dynamic parameters, i.e., shear wave velocity and shear modulus are determined from a dispersion curve of phase velocity with employing the theory of elasticity of soils. In this paper, a developed technique from Spectral Analysis of Surface Waves (SASW), namely as the Wavelet Spectrogram Analysis of Surface Waves (WSASW) is introduced for measurement of the soil dynamic properties at soft marine clay soils sites. This technique has capability to localize the interested response spectrum of surface waves, to reconstructed spectrograms of noisy seismic waves and produces the enhanced phase data to develop the phase velocity dispersion curve. A filtration procedure is also proposed in order to remove the noisy signals from the seismic records received during field measurement. The identification, denoising and reconstruction of the wave response spectrum from seismic surface wave propagation on a soft soil were carried out by using time-frequency analysis of continuous wavelet transforms. The wavelet analysis was used for providing good resolution of spectrogram at low frequency and their spectrograms could be used to clearly identify the various events of interest of the seismic surface waves and noisy signals. Good agreements were obtained between the measured shear wave velocities and the corresponding dynamic shear modulus by the WSASW technique compared to Continuous Surface Wave (CSW), SASW and conventional soil testing method that performed in the same site location. Some good empirical correlations were also obtained as study case for soft soil site

Experimental Investigation of Seismic Parameters and Bearing Capacity of Pavement Subgrade Using Surface Wave Method

The spectral analysis of surface waves (SASW) method is introduced as an in-situ non-destructive seismic technique where the method consists of the generation, measurement and processing the dispersive Rayleigh waves from two vertical transducers. Subsequently, the dispersive data of Rayleigh phase velocity are inverted and the shear wave velocity versus depth of the site is obtained. The dynamic stiffness parameters, i.e. elastic modulus generated from the SASW measurements are at a very small strain levels of 0.001%. At this strain level the soil is linearly elastic and the use of elastic theories is thus justified. The aim of this paper is to investigate the seismic parameters of the pavement subgrade stiffness using the SASW method and to predict its bearing capacity based on the seismic parameters. In order to determine the bearing capacity, in situ dynamic cone penetrometer (DCP) was also carried out in the same location of SASW test.  The relationship of the shear wave velocity and dynamic elastic modulus (Edynamic) of the SASW were found to be in good correlation with bearing capacity obtained by the DCP.

Vertical Deformation and Ballast Abrasion Characteristics of Asphalt-Scrap Rubber Track Bed

Innovations in the field of railroad construction need to be improved, especially in the ballast layer which is an essential structure in conventional railways. The purpose of this study was to analyse the characteristics of vertical deformation and ballast material abrasion with 10% of scrap rubber in two types of sizes (uniform and graded) and with 3% of asphalt. This study uses a compressive test method with six types of samples modeled with ballast boxes measuring 400 x 300 x 200 mm. The test results present that the use of 10% scrap rubber can increase the vertical deformation value significantly to 84%. On the other hand, the use of 3% asphalt can minimize vertical deformation to only 14% because asphalt can increase the ballast layer stiffness. Furthermore, it can also be concluded that in general, the use of 10% scrap rubber and 3% asphalt can reduce the percentage of material abrasion up to 80%. Besides, it also can be known that the use of graded sized scrap rubber material is the most effective in increasing material durability. Scrap rubber and asphalt have the potential to be used together on ballast layers which are expected to be a solution of the problems related to the service-life and ballast maintenance work

An Integration Of The Seismic Methods In Characterization Of An Unsaturated Granitic Residual Soil Site

A comprehensive seismic survey encompassing the seismic refraction and the downhole method have been carried out in order to characterize a site of granitic residual soil.  The seismic refraction was found to be useful in the initial modeling of the subsurface and has managed to identify the water table, a bolder and the bedrock level satisfactorily.  From the downhole seismic, P-wave velocity was found to be responsived to lithology and the water table, while the S-wave velocity was found to be able to characterise the residual soil in terms of their weathering grades.  Correlations between the S-wave velocity (Vs) and dynamic shear modulus (Gseis)  were established with the SPT (N) and the static unload reload shear modulus (Gur)of the pressuremeter tests. The relationship of Vs = 2.89N + 167.84 and Gseis (MPa) = 2.39Gur + 36.03 were obtained in this study. 

Analisis Arus Jenuh dan Panjang Antrian pada Simpang Bersinyal: Studi Kasus di Jalan Dr. Sutomo-Suryopranoto, Yogyakarta

The aim of this paper is to analyse the delay length based on MKJI (1997). A case study was conducted on a signalized junction of Dr.Sutomo-Suryopranoto road, Yogyakarta. The correction was carried out on coefficient of basic saturation flow in ranging from 600 to 2200. Therefore, the predicted (from MKJI 1997) and measured delay length was compared. The results show that the coefficient on basic saturation flow calculation needs to be modified in the range of 600 to 2200 in order to find the similar length of the delay between prediction and field measurement. Passenger car unit (PCU) unit for motorcycle from MKJI (1997) was also corrected from 0.2 to 0.15.

Coupled CWT Spectrogram Analysis and Filtration: New Approach for Surface Wave Analysis (A Case Study on Soft Clay Site)

Surface wave analysis consists of generation, measurement and processing of the dispersive Rayleigh waves recorded from two or more vertical transducers. However, in case of soft clay soil, the reliable dispersion curve is difficult to be produced particularly at the frequency below 20 Hz. Some noises from nature and other human-made sources may disturb the generated surface wave data. In this paper, coupled analysis of continuous wavelet transform (CWT) spectrogram analysis based on Gaussian Derivative function was used to analyze the seismic waves in different frequency and time. First analysis is time-frequency wavelet spectrogram which was employed to localize the interested seismic response spectrum of generated surface waves. Second analysis is a time-frequency wavelet filtering approach which was used to remove noisy distortions in the spectrogram. Based on the generated spectrogram, the thresholds for wavelet filtering could be easily obtained. Consequently, the denoised signals of the seismic surface waves were able to be reconstructed by inverse wavelet transform considering the thresholds of the interested spectrum. Results showed that the CWT spectrogram analysis is able to determine and identify reliable surface wave spectrum and phase velocity dispersion curve of soft clay residual soil. This technique can be applied to problems related to non-stationary seismic wave